By D. Roland. Sarah Lawrence College.
Coronary artery bypass grafts are not performed cheap 35 mg alendronate free shipping, and generally these patients are taken directly to the operating room without undergoing coronary angiography cheap 70 mg alendronate with mastercard. Consequently cheap alendronate 70 mg visa, the interventricular septum remains quite vulnerable to ischemia and occasionally ruptures after myocardial infarction. As with ventricular aneurysm, the anteroapical area is the most common site; it is involved in 65% of patients with ventricular septal rupture. The posterior segment of the septum is involved in 17% of the cases, and the middle segment in 13% of the cases; only 4% of the ruptures involve the inferior segment of the septum. There is frequently a rapid progressive hemodynamic deterioration with myocardial failure following the rupture of the ventricular septum. The initial diagnosis is confirmed by echocardiography and is later followed by cardiac catheterization and coronary angiography. The goal of preoperative management is to decrease the left-to-right shunt by reducing systemic vascular resistance but at the same time ensuring adequate systemic blood pressure and cardiac output. Because these patients tend to die of end-organ failure rather than heart failure, prompt temporary stabilization is achieved with the support of an intraaortic balloon pump, ionotropic agents, and diuretics to maintain optimal tissue perfusion. The operative mortality in this subgroup of patients is relatively high, but without urgent surgery, most of them would not survive. Technique for the Surgical Treatment of a Ventricular Septal Defect the septal defect is approached through an incision parallel to the course of the left anterior descending coronary artery in the center of the left ventricular infarct. With a continuous 3-0 Prolene suture, a generous patch of bovine pericardium is sewn to the left ventricular side of the septum, taking deep bites of normal, healthy muscular tissue as far away from the necrotic rim of the defect as possible. The pericardial patch is then allowed to protrude outside the heart and be incorporated in the ventriculotomy closure. This technique is based on the concept that the higher left ventricular pressure will force the pericardial patch against the entire septum, thereby obliterating the septal defect. The ventriculotomy is then closed with interrupted sutures of 3-0 Prolene with a layer of Teflon felt strip on each side of the incision. When the septal defect is a narrow, slit-like opening in close proximity to the anterior wall of the right ventricle, the sutures are first passed through a strip of Teflon felt, then through the viable septal tissue along the posterior edge of the defect, and again through another strip of Teflon felt on the right ventricular side of the septum. The sutures are brought out through the anterior wall of the right ventricle before they are passed through another strip of Teflon felt. The viable tissue is then reapproximated in a sandwich manner by means of four strips of Teflon felt, one on each side of the septum and one each on the right and left exterior ventricular walls, with a series of interrupted horizontal mattress sutures. The approach to a rupture of the posteroinferior aspect of the septum through the infarcted inferior left ventricular wall is more challenging. Often the posteromedial papillary muscle is also involved in the necrotic process, and concomitant mitral valve replacement may become necessary. Closure of the ventricular septal defect is performed using the patch technique as described in preceding text. Most often, the inferior wall of the ventricle is closed using an appropriately sized Hemashield patch so as not to interfere with the normal geometry of the left ventricle. Coronary bypass grafting is performed judiciously on all bypassable vessels to ensure full revascularization of the remaining myocardium. Percutaneous closure of postinfarction ventricular septal defects has become an alternative strategy in many critically ill patients. This can be done in conjunction with coronary angiography and possible percutaneous coronary revascularization. C: the septal defect and ventricular walls are reconstructed with interrupted sutures incorporating strips of Teflon felt. The very few patients who survive the acute phase may present in congestive heart failure at a later date. By 3 to 4 weeks after acute myocardial infarction, some fibrosis occurs in the necrotic areas so that the tissues are strong enough to hold sutures safely and surgical repair can be performed more easily. In 90% of hearts, the right coronary artery is dominant and supplies the posteromedial papillary muscle. Therefore, infarction of the posterior wall of the left ventricle frequently results in necrosis of the posteromedial papillary muscle. A papillary muscle rupture usually occurs during the first week after infarction or later with reinfarction. Because both leaflets of the mitral valve are attached to each papillary muscle by chordae tendineae, complete disruption of either one, usually the posteromedial papillary muscle, results in gross mitral insufficiency, acute pulmonary edema, and death unless surgical intervention is P. A tear of the apical head of a papillary muscle that supports a small segment of only one of the mitral leaflets may result in a milder degree of mitral regurgitation. If myocardial infarction is not massive and left ventricular function is not severely impaired, these patients can compensate long enough to undergo coronary angiography before semiurgent surgical treatment. Most commonly, conservative surgery will not be adequate because the infarcted papillary muscle is friable and necrotic. Occasionally, a ruptured papillary muscle can be reimplanted, but it may be hazardous if the reimplantation site is necrotic. Mitral valve replacement is the procedure of choice in most patients and can be performed expeditiously with relative safety (see Chapter 6). Coronary artery bypass grafting to bypassable vessels is highly desirable to revascularize the viable myocardium as completely as possible. Significant mechanical complications occurring during the acute phase of myocardial infarction are quite rare. Most patients following myocardial infarction will continue on a medical regimen and live a symptom-free productive life. There is, however, a subgroup of patients who develop symptoms reflecting the effects of chronic changes secondary to an old myocardial infarction. Traditionally, surgical ventricular restoration for ischemic cardiomyopathy has focused on recognizing the borders of the scar tissue and excluding the scar by excision and primary closure or placement of a patch at the junction between scar and normal muscle. The goal of surgery to reconstruct the left ventricle is to achieve a normal-sized cavity and to convert the more spherical shape to a more conical pattern. Cardioplegic arrest of the heart is accomplished by infusion of cold blood cardioplegic solution through the aortic root after clamping the aorta. This is complemented by infusion of cold blood cardioplegia into the coronary sinus by the retrograde technique (see Chapter 3). The scar segment of the left ventricular wall, devoid of myocardium, tends to be sucked in by the vent suction. The opening is then enlarged, and some excess scar tissue may be excised to provide easy access for removal of blood clots from within the left ventricle and/or aneurysm wall. Adherent Calcified Aneurysm Wall Occasionally, there may be marked fibrous reaction or even calcification of the aneurysm wall, making its mobilization tedious and time-consuming.
For some types of illness cheap alendronate, such as a precariously positioned tumor discount alendronate generic, allowing patient/family to view images with support from a clinical team member to assist in interpretation safe 35mg alendronate. Use available resources, such as white boards or electronic devices, which can help convey information or display images. Depending on the level of certainty about medical options and prognosis and patient/family preferences, communication strategies for shared decision-making may emphasize paternalism or patient autonomy . Many providers are trained to have awareness of body language, eye contact, tone, and pacing of their speech. Just as clinicians must wash their hands to avoid bringing germs to the patient’s bedside, they must take a moment to reflect on what emotions they carry. Practitioners who enter the patient’s or family’s space carelessly or fail to maintain a professional appearance and countenance can inadvertently sabotage the clinical encounter before it even begins. Remove distractions from the setting, such as turning off televisions, silencing non-essential alarms and phones, and placing a sign on the door to request privacy, and warning if an interruption may occur. If the patient is incapacitated, determine with the family whether the meeting should be held with the patient present; if so, portray respect and acknowledge the patient’s guiding “voice,” even if s/he is unable to participate. Step 2–Make Introductions and Share Intentions for the Meeting: While healthcare team members can prepare extensively for a family meeting, family members may have only moments to understand who is going to be speaking to them and why. Providing business cards of team members and offering materials to write down information can reduce distress. Shaking hands, making good eye contact, offering a gentle smile, and bowing the head slightly can demonstrate respect, and sitting down sends a message of being willing to give time and attention . Asking about proper pronunciation of patient’s name or whether a nickname is preferred signals that the patient will be treated as a valued individual. Step 3–Assess Patient/Family Understanding: It is easy to assume that patients or families “should” understand the diagnosis or prognosis based on prior conversations or the amount of time that a patient has been ill. Only by asking patients/families to share perspectives can the clinician gain insight into what the patient or family know. When traumatic events have occurred, the act of telling the story to an empathetic clinician helps the patient and family to accept what has occurred and improves satisfaction with care . Open-ended questions should be used to explore the patient or family’s perception, resisting the urge to assume that broad comments such as “he’s really sick” mean the same thing to everyone. A technique called “ask-tell-ask” reminds clinicians to respond with questions rather than commentary. It is the feeling of being listened to that correlates with positive impressions of the clinician . Allowing the patient or family to speak first allows the health professional to carefully assess factors such as emotional readiness to hear difficult information or make decisions, patient and family’s health literacy, culture, any existing conflict within the family, and perspective on illness. If the topic of concern will not be covered in the meeting, the clinician can at least validate it and provide reassurance that the issue will be addressed in the future. Step 4–Give a Concise Medical Review in Clear Language: A clinician summary can add recent events or details that inform the decision at hand and, by repeating back elements of the patient/family summary, events are placed in context. It can be helpful to ask what level of information is preferred: “Some families like a lot of detail about the clinical side, while others want to focus on the big picture—do you know what you prefer? Step 5–Allow Silence and Respond to Emotion: Response to emotion is critical at every point in the interaction. Discomfort with strong emotions is common, and failing to respond appropriately to emotions early in the interaction will limit the patient and family’s trust in the clinician. Dire news is often difficult to accept and the perception that the clinician does not care provides a tempting reason to discount clinical opinions. For the medical caregiver, years of training emphasizing the importance of clinical knowledge and detail can create a reflexive desire to present more medical information than is valuable. Well-intended efforts to reiterate clinical information may fall on deaf ears and hinder efforts by the patient or family to express themselves. Family members who have suddenly lost eye contact or physically withdraw (leaning back, looking away, bowing the head, or crossing arms) may be indicating the need to pause. Asking if a break is needed, leaning in, or—if culturally appropriate and natural to the clinician—reaching gently forward to touch the other person are subtle ways to offer support. In the concept of naming emotion, the clinician begins by taking a step back to identify what emotion is being expressed. It is important to notice that anger may actually be rooted in another feeling, such as fear or shame. Rather than making a declarative, somewhat presumptive statement such as “you seem angry,” normalize the emotion by saying “sometimes people begin to feel angry after talking about something like this. Tears may be a common response to difficult news and, while it may be uncomfortable to sit quietly, it is often the best response. It is important to listen without defensiveness for areas where something can be done to allay the cause of the anger. Resist the urge to either make pacifying statements or become angry yourself, exhibit non-threatening body language, and speak calmly to prevent anger from overwhelming the interaction. Anger is often secondary to other emotions, namely fear and guilt; gently identifying the sources of these underlying emotions can help defuse the anger. Families may fear that care at home was not adequate, that “signs” were missed, and fear future guilt and blame if the patient does not survive. Emphasizing that clinicians share in the lack of control over irreversible illness reduces guilt and builds the team’s partnership with family members to care for their loved one—especially if they cannot collectively “fix” the situation . Showing sadness when giving bad news with statements of emotion (“I am worried that your body is not improving with treatment”) helps the patient and family to absorb the nature of the news. Clinicians who remain upbeat when giving bad news leave families thinking that the news was “mixed” due to incongruence of message and messenger, while those who withdraw without emotional expression add confusion and feelings of abandonment. Immediately discounting an outcome for which patients express hope can damage trust, yet it is imprudent to offer false hope in the form of non-beneficial treatments. An effective approach can be to simultaneously “hope for the best and prepare for the worst,” which allows the team to acknowledge the patient and family’s hopes while setting the stage for end-of-life planning. Family meetings allow everyone involved in a patient’s care to process strong emotions, grasp medical realities, and find hope in shared and realistic goals.
Another strategy in this clinical situation is the use of the Heartstring System if a soft spot on the ascending aorta can be identified order alendronate 35 mg free shipping. However purchase alendronate 35mg with amex, it is typically performed after bypass grafting is completed buy alendronate with paypal, while the patient is still on cardiopulmonary bypass. The laser is fired to create between 15 and 20 channels 1 cm apart, covering the ischemic but not directly the revascularized area. Bubbles are seen by transesophageal echocardiography when the laser beam reaches the ventricular cavity, confirming a completed channel. After cardiopulmonary bypass is discontinued and protamine is administered, most channels readily seal at the epicardial surface with gentle digital pressure. If a patent in situ right internal thoracic graft is present and crossing the midline, or if a redundant left internal thoracic pedicle lies directly beneath the sternum, great care must be exercised to prevent injury to these grafts. If a patent in situ internal thoracic graft is present, the pedicle must be identified and mobilized if the redo procedure is to be done on cardiopulmonary bypass with cardioplegic arrest of the heart. The safest technique for identifying the left internal thoracic pedicle is to begin the dissection from the diaphragm and proceed superiorly. The anastomotic site is therefore encountered first, and the pedicle can then be gently encircled for later clamping. If repair and reestablishment of flow is not feasible, urgent initiation of cardiopulmonary bypass is advisable. Alternatively, the injured graft may be cannulated with an olive-tipped catheter and perfused with a line connected to an aortic or femoral artery catheter. It is important to evaluate the patient preoperatively for the availability and quality of remaining conduits. This may entail Doppler studies to identify residual greater saphenous vein segments or usable lesser saphenous vein. At the time of angiography, it is useful to inject any internal thoracic vessel not previously used to demonstrate its patency. Occasionally, the internal thoracic vessels are injured or occluded during chest closure, and therefore would not be available as conduits for the reoperation. This strategy also reduces the number of proximal anastomotic sites on an already overcrowded and scarred ascending aorta. The ascending aorta is often quite thickened and diseased in patients undergoing redo coronary artery procedures. Therefore, it is generally safer to perform all distal and proximal anastomoses under a single aortic cross-clamp period. The hood of the old vein graft is usually free of disease and provides a good location for a proximal anastomosis. The patent arterial grafts often provide satisfactory sites for the proximal anastomosis of short arterial grafts. Patent but diseased saphenous vein grafts should not be manipulated to prevent embolization of debris into the distal coronary artery bed. Some controversy exists as to whether antegrade cardioplegia should be administered down diseased vein grafts. Some surgeons divide all old, patent vein grafts once on cardiopulmonary bypass and flush debris out of them with retrograde cardioplegia. Inadequate Flow through Internal Thoracic Artery An internal thoracic artery may not provide sufficient flow to a previously grafted coronary artery with a diseased but patent vein graft. This is especially true if the surgeon elects to divide and oversew the old graft to prevent embolization of debris. How to deal with a patent or stenotic vein graft when an internal thoracic artery is to be used is somewhat controversial. In our practice, we tend to leave the old vein graft intact and anastomose the internal thoracic artery to the coronary just distal to the old graft. If there is not an anastomotic stenosis, a 1-mm rim of the old vein graft is left at the distal anastomotic site and the new vein graft is sewn to it. Alternatively, another vein graft and the internal thoracic artery may be connected to this coronary artery, with the risk of competitive flow causing a string sign of the arterial conduit. Often the coronary artery disease has progressed and given rise to new stenotic lesions distal to the occluded graft. In such situations, the occluded graft must be replaced to provide perfusion to the proximal coronary bed. If dissection is carried out superiorly to locate the pedicle, the lung tissue is frequently injured in multiple locations. If the internal thoracic pedicle cannot be safely found, the surgery may be performed as an off-pump procedure or on cardiopulmonary bypass with deep hypothermic arrest. The onset of ischemia is usually heralded by pain that may be followed by shock and ventricular failure owing to significant myocardial injury. The severity of symptoms and clinical manifestations are intimately related to the magnitude of myocardial necrosis and loss of contractile strength. Necrosis of the ventricular septum may result in an acute septal defect and sudden left-to-right shunt, leading to hemodynamic instability. Necrosis of papillary muscles will result in papillary muscle dysfunction or rupture, causing severe mitral valve insufficiency. Patients are initially stabilized with medical management and intraaortic balloon counterpulsation before undergoing cardiac catheterization and coronary angiography. Concomitant coronary artery bypass grafting should always be contemplated, whenever possible, to achieve complete myocardial revascularization. A small subgroup of these patients may compensate and present late with a pseudoaneurysm, left ventricular aneurysm, ventricular septal defect, or ischemic mitral valve insufficiency. Venous drainage is accomplished through bicaval cannulation, although a single large atrial cannula is adequate whenever the right heart remains a closed system during the procedure. Contained Bleeding within the Pericardium When there is evidence of contained bleeding within the pericardium due to a pseudoaneurysm or rupture of the heart, it is prudent to cannulate the aorta through a small enough opening in the pericardium overlying the aorta to allow volume replacement during venous cannulation and initiation of cardiopulmonary bypass. Cardiogenic Shock Most patients requiring surgical intervention for management of acute mechanical complications of myocardial infarction are in cardiogenic shock. Cardiopulmonary bypass is initiated, and the heart is decompressed by a vent catheter introduced into the main pulmonary artery or through the right superior pulmonary vein into the left ventricle. Cold blood cardioplegic solution is then administered through the aortic root followed by retrograde delivery into the coronary sinus (see Chapter 3). Through a rent in the ventricular endocardium, blood gradually leaks into the area of infarction and distends the necrotic tissue.
Damus Modification In some patients order alendronate with mastercard, most notably those with double inlet left ventricle purchase alendronate discount, or those with double outlet right ventricle and mitral valve atresia buy 35 mg alendronate amex, it is preferable to perform a modified Blalock-Taussig shunt, so as to eliminate the need for a left ventriculotomy, and also for ease because of the size of the reconstructed great vessel. Coronary Artery Compromise Meticulous technique must be used when anastomosing a small ascending aorta to the proximal portion of the pulmonary artery to avoid obstructing flow into the coronary arteries. Some advocate an incision into the sinus of the pulmonary valve so as to increase the area of connection between the diminutive aorta and the pulmonary artery. Modified Patch Technique Some surgeons use a homograft patch to enlarge the entire opening beginning in the descending aorta, across the aortic arch, and down the ascending aorta to just above the sinotubular junction. An incision is made in the patch under the aortic arch, and the pulmonary base is anastomosed to this opening. A disadvantage of this technique is the lack of growth potential of the homograft patch, which is circumferentially attached to the pulmonary base. The innominate, left carotid, and left subclavian arteries are snared down during low-flow cerebral perfusion. The opening is carried proximally along the inferior aspect of the aortic arch to the level of the innominate artery. The distal opening may be connected to the incision on the inferior aspect of the aortic arch (dotted line). Small Ascending Aorta If the ascending aorta is less than 3 to 4 mm in diameter, it is transected distally near the takeoff of the innominate artery and the distal opening is connected to the aortic arch incision or is closed with a separate running suture. If the main pulmonary artery is of good length, it can be anastomosed directly into the opening on the aortic arch with no patch material. The suture line is begun at the distal opening on the descending aorta using double-armed 7-0 Prolene suture. The needle is first passed from inside to outside on the pulmonary artery base and then outside to inside on the aorta. The second needle is used to complete the suture line anteriorly starting inside to outside on the descending aorta and continuing along the arch until the first suture line is met. Inadequate Mobilization of the Descending Aorta the descending aorta must be aggressively mobilized at least 1 cm beyond the ductal insertion to allow a tension-free anastomosis. The curved clamp placed on the descending aorta helps to hold it in place and provides improved exposure for the distal extent of the anastomosis. Inadequate Length of the Main Pulmonary Artery the takeoff of the right pulmonary artery is variable in its proximity to the pulmonary valve. When it is located more proximally, the transected main pulmonary artery may not be long enough to reach the aortic arch. A rectangular or oval piece of pulmonary homograft is then used to augment the posterior aspect of the opening in the arch and descending aorta. The pulmonary base can then be sewn to the pulmonary homograft patch posteriorly and directly to the aortic arch anteriorly. Inadequate Aortopulmonary Window A direct anastomosis of a short pulmonary base to the arch may result in narrowing of the aortopulmonary window by pulling the arch inferiorly and the neoaortic root posteriorly. This can result in compression of the left pulmonary artery or left bronchus with serious consequences. Extension of Ductal Tissue In some patients, the ductal tissue extends into the aortic arch between the left carotid and left subclavian arteries. Others have a long ductus, which results in a short descending aorta after the ductal tissue is excised. Incision on Descending Aorta Some surgeons advocate making a 5- to 10-mm opening on the medial aspect of the transected descending aorta P. If the ascending aorta has been transected, it is now trimmed to a length of 10 to 15 mm and the open end is beveled. Note the probe introduced through the open arch anastomosis to prevent purse-stringing of the ascending aortic suture line. Too Long an Ascending Aorta If the diminutive aorta is left too long, it may kink, thereby causing coronary ischemia. Purse-Stringing the Anastomosis When the ascending aorta is 2 mm or less in diameter, the suture line of the main pulmonary artery to aortic arch may be left untied. More recently, many centers have adopted a right ventricle-to-pulmonary artery graft to provide pulmonary blood flow. The potential advantages of this shunt include a higher diastolic blood pressure in these patients, leading to improved coronary perfusion, and a decreased risk of shunt thrombosis perioperatively. Some questions remain regarding the optimal shunt size and material, the effect on pulmonary artery growth, and the impact of the right ventriculotomy on ventricular function. After transecting the main pulmonary artery just below the bifurcation, an appropriate site for the right ventriculotomy is marked on the right ventricular outflow tract. The confluence patch with the attached Gore-Tex tube is anastomosed to the opening at the pulmonary artery bifurcation. Right Ventricle-Pulmonary Artery Shunt During rewarming, a right ventriculotomy is made at the previously marked site. The proximal end of the tube graft is cut obliquely at the appropriate length and anastomosed to the ventriculotomy. To facilitate the second-stage procedure, some surgeons place the conduit from the right ventricle to the right pulmonary artery on the right side of the neoaorta. This may make removal of the prosthetic material easier, and simplify the reconstruction of any anastomotic narrowing. The standard left-sided shunt can also be encircled with a strip of Gore-Tex tape or Silastic that is left long and positioned in front of the neoaorta. Although many centers have adopted this technique, the long-term implications of this procedure are unknown. However, this source of pulmonary blood flow may be particularly applicable in low-birth-weight patients in whom a 3. The first is the so-called “dunk” technique in which 2 to 3 rings of the ringed Gore-Tex tube graft are inserted into the ventricular cavity and the graft secured with four tacking sutures and two purse-string sutures. Others have advocated for creating a hood on the proximal graft of homograft so as to reduce the angulation required in a direct connection. Gore-Tex Graft on Innominate Artery If a right ventricle-pulmonary artery shunt is constructed, the tube graft sewn to the innominate artery is occluded with a large metal clip near the anastomosis, cut short, and the end oversewn. Systemic-Pulmonary Shunt When selective cerebral perfusion has been performed, and a modified Blalock-Taussig shunt is desired, a new neoaortic cannula is placed and pump outflow transitioned to the new cannula. Shunt Placement on Pulmonary Artery the distal end of the shunt should be placed as centrally as possible, close to the oversewn ductus on the proximal pulmonary artery. In addition, it may allow the bidirectional Glenn procedure to be performed without cardiopulmonary bypass (see Chapter 31).