Postcardiotomy mechanical circulatory support in the elderly

The role of mechanical circulatory support after cardiac operations in elderly patients is not clearly established. Between November 1985 and July 1989, 18 patients 65 years of age or older (mean age, 71 years; range, 65 to 82 years) were treated after cardiotomy with a centrifugal vortex or pneumatic mechanical ventricular assist device. This group comprised 1.9% of the 926 patients 65 years of age or older undergoing cardiac surgical procedures and 69% of the 26 patients requiring postcardiotomy support during this interval. Before institution of mechanical support, all patients were receiving maximal inotropic support and 16 patients had intraaortic balloon pumps inserted. Univentricular support was used in 9 patients (6 left, 3 right) and biventricular support in 9 patients. The mean duration of support was 45 hours (range, 8 to 118 hours). Twelve patients (67%) were successfully weaned, 8 (44%) were discharged from the hospital, and 6 (33%) remain alive 11 to 31 months postoperatively. Four of the 6 survivors are in New York Heart Association class I, 1 is in class II, and 1 is in class IV. The Combined Registry for ventricular assist device support has recently reported an overall survival rate of 12% in patients 65 to 70 years of age and 6% in those older than 70 years. Our results are comparable with those reported for younger patients and justify the use of postcardiotomy ventricular assist device support in the elderly.

Use of single internal mammary artery grafts in older patients

The indications for use of the internal mammary artery as a coronary bypass conduit in older patients are not clearly established. Between January 1985 and December 1988, 786 patients received single internal mammary artery grafts alone (717) or in conjunction with other procedures (69). Of these patients, 341 were 65 years of age or older (mean, 69.3 years). This group was compared with those patients less than 65 years of age (mean, 56.2 years). There were no significant differences between the two groups in the incidence of diabetes mellitus; the number of distal coronary anastomoses; left ventricular wall motion score; the frequency of isolated bypass procedures, reoperations, or emergent operations; or the durations of aortic clamping and cardiopulmonary bypass. The older group contained more women (34.9% versus 20.7%) and more patients with left main coronary artery disease (15.5% versus 9.4%) (p less than 0.01). No significant differences in the frequency of reoperation for hemorrhage, perioperative infarction, neurological deficits, requirements for intra-aortic balloon pumping, sternal wound infections, necessity for prolonged ventilatory support, or 30-day mortality (2.7% versus 3.2%) were observed. The length of postoperative hospitalization was greater in the older group (11.8 versus 10.2 days) (p = 0.02). Blinded histological examination of biopsies from 61 internal mammary artery grafts (34 patients less than 65 years, 27 patients greater than or equal to 65 years) showed no significant differences in luminal area or wall thickness. No significant degenerative changes were observed in either group. We conclude that the use of the internal mammary artery for bypass grafting in older patients is safe and may provide long-term benefit.

Elective hypothermic cardiopulmonary bypass and circulatory arrest for spinal cord protection during operations on the thoracoabdominal aorta

Resection of aneurysms of the entire descending thoracic aorta and segments of the abdominal aorta is associated with a substantial incidence of spinal cord ischemic injury, particularly in patients with aortic dissection. Since hypothermia has a protective effect on spinal cord function, we evaluated a technique of total cardiopulmonary bypass with periods of hypothermic circulatory arrest and low flow (rectal/bladder temperatures of 15 degrees to 19 degrees C) in five patients requiring replacement of the entire descending thoracic and the upper abdominal aorta and judged to be at high risk for the development of spinal cord injury. All patent lower intercostal and lumbar arteries were preserved or reimplanted during the hypothermic interval. There was one hospital death. None of the four survivors had a new spinal neurologic deficit, renal or cardiac dysfunction, or required reoperation for bleeding. Transfusion of blood products was not excessive. Severe pulmonary dysfunction necessitating tracheostomy occurred in one patient and contributed to his death 7 weeks postoperatively. The remaining three patients are well 8 to 36 months postoperatively. This initial experience suggests that hypothermic perfusion and circulatory arrest can be safely implemented in selected patients who require extensive aortic resections and who are at substantial risk for the development of spinal cord injury. Further evaluation of this technique is warranted.

Risks of bilateral internal mammary artery bypass grafting

Although use of one internal mammary artery (IMA) for coronary artery bypass grafting does not appear to be associated with increased risk, the results with both IMAs are less certain; the potential for a higher incidence of sternal wound infection as a result of devascularization of the sternum is a major concern. During a 42-month interval ending July 1988, 1,566 patients had coronary artery bypass grafting alone or in combination with other procedures: 633 received only vein grafts, 687 had unilateral IMA grafting, and 246 had bilateral IMA grafting. The IMA patients were younger, were more often male, had better cardiac function, and underwent fewer emergent, urgent, or combined procedures than the patients receiving vein grafts (p less than 0.05). Thirty-day mortality was lower among the IMA patients (unilateral IMA group, 2.8%; bilateral IMA group, 3.7%; and vein graft group, 7.9%; p = 0.001). With the exception of sternal wound problems, occurrence rates for postoperative complications among the IMA patients did not differ significantly from or were lower (p less than 0.05) than those among the patients with vein grafts. Sternal infections occurred with greater frequency among the bilateral IMA patients (6.9%) than among the unilateral IMA (1.9%) or vein graft (1.3%) patients (p = 0.001). By univariate analysis, obesity, diabetes, bilateral IMA grafting, and need for prolonged (greater than 48 hours) mechanical ventilation were associated with a significantly higher incidence of sternal infection (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Single lung transplantation for severe chronic obstructive pulmonary disease. Washington University Lung Transplant Group

Single lung transplantation (SLT) has been considered physiologically inappropriate for patients with chronic obstructive pulmonary disease (COPD). It has been postulated that the high static compliance and elevated pulmonary vascular resistance of the native lung functioning in parallel with the more normal allografted lung could cause unacceptable ventilation-perfusion mismatching and/or overinflation of the native lung with encroachment on the expansion of the transplanted lung. While some degree of ventilation-perfusion imbalance may be physiologically obligatory after SLT for COPD, a significant disruption in gas exchange may not occur unless a complication, such as rejection or infection, arises in the transplanted lung. A 60-year-old man with COPD who underwent successful SLT is presented and discussed. In spite of scintigraphic evidence of ventilation-perfusion mismatching between the native lung and the allograft during the first six postoperative weeks, the recipient had normal resting gas exchange on room air after the second postoperative week. Fourteen weeks after transplantation, his maximum oxygen uptake was 37.3 percent of the predicted maximal value, and no evidence of ventilatory limitation was detected. His functional status and lifestyle have been markedly improved by SLT. The role of SLT for COPD should be reconsidered. It may be a reasonable transplantation alternative for selected patients with COPD who are not candidates for double lung transplantation (DLT).

Intraoperative ultrasonic imaging of the ascending aorta

Embolization of atherosclerotic material from the ascending aorta resulting from placement of cannulas or vascular clamps is a major cause of stroke during cardiac surgical procedures. In an effort to identify atherosclerotic disease of the ascending aorta which might predispose to embolization, intraoperative B-mode ultrasonography was performed in 50 patients. The aorta was imaged from the aortic annulus to the origin of the innominate artery in transverse and longitudinal views. The results were compared with visual and tactile examination of the aorta for the presence of atherosclerosis. Ultrasonic imaging demonstrated atherosclerotic disease in 29 patients (58%). Visual examination and palpation identified atherosclerosis in 12 patients (24%). The amount and location of plaque was sufficient to require a change in the site of arterial cannulation or the proximal vein graft anastomoses or the technique of cardiopulmonary perfusion in 12 of the 50 patients (24%). All 12 patients were 65 years of age or older. Palpation underestimates the presence of atherosclerotic disease in the ascending aorta. Intraoperative ultrasonography accurately identifies patients with atherosclerotic disease of the ascending aorta. This allows the surgeon to modify cannulation, perfusion, and operative techniques to reduce the risk of perioperative stroke due to the embolization of atherosclerotic debris from the ascending aorta.

Coronary artery bypass grafting for postinfarction angina pectoris

The variables that predict increased operative risk and postoperative morbidity among patients who undergo coronary artery bypass grafting (CABG) early after myocardial infarction for persistent or recurrent ischemia are incompletely defined. In a recent 3-year interval (1985-1987), 240 patients underwent CABG within 30 days of a documented myocardial infarction. Thirty-day mortality was 3.3% (eight patients). Twenty variables were examined by univariate and multivariate analysis for their effects on early mortality. Left main coronary artery disease (p = 0.0003), female sex (p = 0.0059), and preoperative left ventricular dysfunction (increased left ventricular wall motion score) (p = 0.0135) were significant independent predictors of increased 30-day mortality. Postoperative inotropic support for low cardiac output was required for 55.6% of patients operated upon within 24 hours of infarction as compared with 11.6% of patients operated upon between 1 and 30 days (p less than 0.01). Significantly more patients undergoing emergent CABG required postoperative intra-aortic balloon pumping and inotropic support than those patients who underwent urgent or elective operation (23.8% vs. 4.6% and 52.4% vs. 10%, respectively) (p less than 0.01). Other studies confirm that preoperative left ventricular dysfunction, presence of cardiogenic shock, or intra-aortic balloon pumping are important predictors of operative risk. Other variables that may be important include advanced age, female sex, left main coronary artery disease, and anterior transmural infarction. The timing and urgency of operation have not been shown to be significant and independent determinants of increased operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased complications and prolonged hospital stay in elderly cardiac surgical patients with low serum albumin

Cardiac surgery in elderly patients is associated with acceptable operative mortality but an increased complication rate. Malnutrition is common in the elderly and may adversely affect surgical outcome. To determine the effect of hypoalbuminemia on postoperative complications, 92 patients greater than or equal to 75 years (range 75 to 90) undergoing a variety of major cardiac surgical procedures were evaluated. Thirteen patients (14%) had a serum albumin level less than 3.5 g/dl preoperatively. Compared to patients with normal albumin, hypoalbuminemic patients had an increased frequency of postoperative confusion, congestive heart failure, low cardiac output, renal dysfunction and gastrointestinal complications (all p less than 0.05). Mean postoperative length of stay was markedly prolonged in these patients (27 vs 12 days; p less than 0.001), and mortality also tended to be higher (31 vs 13%; p = 0.11). Using multivariate analysis, albumin less than 3.5 g/dl was the most powerful predictor of postoperative renal dysfunction (p less than 0.01), and was also an independent predictor of increased length of stay (p less than 0.01) and gastrointestinal disorders (p less than 0.05). Thus, hypoalbuminemia is a powerful indicator of an increased risk of perioperative complications in elderly patients undergoing cardiac surgery. Increased attention to nutritional factors is warranted in these patients.

Treatment of life-threatening ventricular arrhythmias with nonguided surgery supported by electrophysiologic testing and drug therapy

Forty-six patients who had coronary artery disease, left ventricular aneurysm and life-threatening ventricular tachyarrhythmia underwent surgical treatment to eliminate or facilitate control of the arrhythmia. Surgery was performed without the assistance of intraoperative mapping techniques. Forty-three patients underwent preoperative or postoperative electrophysiologic testing, or both, and antiarrhythmic therapy was added, when indicated, postoperatively. The patients had a mean age of 63 years, a mean preoperative left ventricular ejection fraction of 27 +/- 9% and a mean preoperative left ventricular end-diastolic pressure of 23 +/- 9 mm Hg. Twenty-one patients (46%) underwent surgical treatment within 2 months of their last myocardial infarction. The overall operative mortality rate was 6.5% (three patients). Eighteen of the 43 operative survivors were discharged from the hospital on no antiarrhythmic therapy, whereas 25 received additional antiarrhythmic treatment. During a mean follow-up period of 36 months (range 2 to 88), there were 13 deaths; eight patients died suddenly, three died of congestive heart failure, one of myocardial reinfarction and one from a noncardiac cause. The overall cumulative cardiac mortality rate at 1, 2 and 3 years was 16, 22 and 35%, respectively, whereas the sudden cardiac death rate was 5, 12 and 20%, respectively. This experience suggests that high risk patients who undergo nonguided surgery for life-threatening ventricular arrhythmia and left ventricular aneurysm have a relatively low surgical mortality and a better long-term survival than previously reported. However, if utilized, such an approach must be systematically supported by perioperative electrophysiologic testing to determine the need for supplemental antiarrhythmic therapy.

Carotid endarterectomy based on duplex scanning without preoperative arteriography

Between July 1985 and September 1987, 25 patients underwent 26 carotid endarterectomies based on an abnormal duplex scan (B-mode ultrasonography and pulsed-Doppler sound spectral analysis) indicative of severe stenosis or ulceration. Arteriography was not performed because of severe unstable angina requiring coronary artery bypass grafting (23 patients) or patient preference (two). Twelve patients were symptomatic, and 13 were asymptomatic but had severe (greater than or equal to 75%) bilateral or unilateral carotid artery stenosis. Operative and pathological analyses confirmed the duplex-scan findings in all 25 cases. All 25 patients survived the operation. One patient had a transient ipsilateral neurological deficit, and one had a permanent contralateral neurological deficit. Five patients died of ventricular arrhythmias within 30 days of operation. Duplex scanning is an accurate method for determining the presence of clinically and hemodynamically significant carotid arterial occlusive disease. Duplex scanning also serves as an alternative method for evaluating patients for whom carotid arteriography may be associated with significant risk.

Management of recurrent superior vena caval syndrome with an externally supported femoral vein bypass graft

Management of superior vena caval syndrome with an autogenous vein bypass graft can be complicated by occlusion of the bypass graft. The case of a patient with recurrent superior vena caval syndrome due to occlusion of a spiraled saphenous vein graft who was managed with a femoral vein graft supported externally by a sleeve of ringed polytetrafluoroethylene is presented. A venogram demonstrated patency of the graft 11 months postoperatively, and the patient remains free from clinically apparent superior vena caval obstruction 18 months postoperatively.

The coronary-subclavian steal syndrome: report of a case and recommendations for prevention and management

The coronary-subclavian steal syndrome involves the siphoning of blood from the myocardium through an internal mammary artery graft because of a proximal subclavian artery stenosis or occlusion, and results in myocardial ischemia. With the increased use of the internal mammary artery for myocardial revascularization, the potential exists for recurrence of angina pectoris in patients who have or in whom develops high-grade stenosis or occlusion of the subclavian artery, because of the coronary-subclavian steal syndrome. The coronary-subclavian steal syndrome can be prevented by the identification of patients with or at risk to develop subclavian artery occlusive disease. All patients undergoing cardiac catheterization prior to coronary artery bypass grafting in which use of the internal mammary artery is anticipated should be evaluated for the presence of upper extremity and cerebrovascular ischemia, the presence of cervical or supraclavicular bruits, and an upper extremity blood pressure differential of 20 mm Hg or greater. Patients with these findings or with evidence of diffuse atherosclerotic vascular disease should have brachiocephalic arteriography at the time of coronary arteriography to identify significant subclavian artery occlusive disease. When this is demonstrated, use of the internal mammary artery as a free graft instead of an in situ graft or use of saphenous vein grafts is indicated. Patients in whom recurrent angina develops following coronary artery bypass grafting that included an internal mammary artery graft should have coronary arteriography to evaluate the presence of coronary-subclavian steal syndrome, and brachiocephalic arteriography. Carotid-subclavian bypass grafting, probably best done with a prosthetic conduit, is the procedure of choice for management of the coronary-subclavian steal syndrome.

Outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave valve: current information and recommendations for patient care

Mechanical failure of artificial heart valves can be a catastrophic event. The problem of outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave tilting disc prosthesis has received much attention in the medical literature and generated both concern and confusion among patients and physicians. Analysis of current data from the manufacturer, as well as a review of the medical literature, suggests that the overall risk of outlet strut fracture is low and that elective explantation of a well functioning Björk-Shiley 60 degrees Convexo-Concave valve prosthesis is not warranted. Diagnostic features of outlet strut fracture can be seen with overpenetrated chest X-ray films so that diagnosis can be established promptly. Early operation to replace the fractured prosthesis is essential for patient survival.

Report of the Ad Hoc Committee on Risk Factors for Coronary Artery Bypass Surgery

The Society of Thoracic Surgeons remains greatly concerned about the use of raw mortality data as the sole measure to determine quality of care following coronary artery bypass surgery. Use of such data without consideration of risk factors that are predictors of hospital mortality and of other indices of quality of care is inappropriate and misleading and may adversely affect the care of the high-risk cardiac surgical patient. The Society is committed to the principle of providing the public with accurate information regarding the conduct of coronary artery surgery. However, it believes that the data provided by HCFA do not provide this information and should not be used as the sole index of quality of care following coronary artery bypass surgery.

Direct noninvasive monitoring of spinal cord motor function during thoracic aortic occlusion: use of motor evoked potentials

Spinal cord monitoring during thoracic aneurysmectomy by somatosensory evoked potentials has been criticized for its failure to measure anterior (motor) spinal cord function. We have developed a clinically applicable, noninvasive technique for intraoperative monitoring of motor evoked potentials (MEP), which allows direct functional assessment of spinal cord motor tracts during thoracic aortic occlusion. Twelve dogs underwent continuous intraoperative monitoring of MEP before, during, and after thoracic aortic cross-clamping. Motor tract response to noninvasive cord stimulation (5 to 10 mA, 0.02 msec, 4.3 H2) was recorded by subcutaneous electrodes placed along the length of the spine (T-10, L-1, and L-4). Six animals (group I) subjected to aortic cross-clamping alone demonstrated a characteristic time- and level-dependent deterioration and loss of MEP. Ischemic cord dysfunction (as determined by time from clamping to loss of MEP) progressed from the distal to the proximal cord (L-4 = 11.3 +/- 1.5 minutes; L-1 = 14.9 +/- 2.3 minutes; T-10 = 16.9 +/- 2.3 minutes; p less than 0.05 between all levels). Reperfusion of the distal aorta 20 minutes after clamping resulted in MEP return that progressed from the proximal (T-10) to distal (L-1 and L-4) cord. In another six animals (group II), distal perfusion (mean blood pressure = 95 mm Hg) was maintained for 1 hour after cross-clamping by left atrial-femoral artery bypass. Normal configuration and amplitude of MEP was maintained throughout the cross-clamping period. These data suggest that distinctive changes in MEP indicative of reversible ischemia of spinal cord motor tracts occur after aortic cross-clamping. Such ischemia begins in the most distal cord, exhibits upward progression with time, and can be prevented by maintenance of adequate distal aortic perfusion. Clinical use of MEP monitoring during thoracic aneurysmectomy may provide a method for intraoperative assessment of the adequacy of motor tract perfusion.

Evolving concepts in prevention of spinal cord injury during operations on the descending thoracic and thoracoabdominal aorta

Spinal cord injury following operations on the descending thoracic or thoracoabdominal aorta remains a major problem. In certain subsets of patients, the risk of postoperative spinal cord injury is substantial. Although several adjuncts have been employed clinically to eliminate or reduce the frequency of this complication, none have proven to be completely effective. An important reason for this is the failure of these techniques to reliably and noninvasively localize the level of origin of arteries from the aorta that are critical to spinal cord circulation. Since postoperative spinal cord injury most likely results from ischemia or hypoxia of the lower segment of spinal cord, use of adjunctive techniques to preserve spinal cord function during aortic clamping by perfusing the distal aorta adequately with or without systemic hypothermia should be considered. To practically implement this, partial cardiopulmonary bypass for distal perfusion when the critical intercostal or lumbar arteries originate from the aorta distal to the excluded segment, and total cardiopulmonary bypass with systemic hypothermia and implantation of intercostal and lumbar arteries when these arteries originate from the excluded segment, can be used. In addition, whenever possible, intraoperative monitoring of spinal cord function should be performed.

Preparation of valved conduits by plasma immersion and autoclaving

A method is described for preparing the graft portion of a manufactured valved conduit by plasma immersion and autoclaving while protecting the attached mechanical valve from coagulum and debris.

Eleven-year experience with composite graft replacement of the ascending aorta and aortic valve

Between September, 1974, and December, 1985, 127 patients had replacement of the ascending aorta and aortic valve with a composite graft. Annuloaortic ectasia was the most common indication for operation (69 patients), followed by aortic dissection (51 patients). Twenty-four patients (19%) had the Marfan syndrome. Hospital mortality was 4.7%. Emergent operation for acute dissection was the only independent predictor of hospital death (p = 0.03). Reoperation for postoperative hemorrhage was required in 15 patients (11.8%) and for prosthesis-related complications (pseudoaneurysm, prosthetic endocarditis, technical problems, and valve thrombosis) in 16 patients (12.6%). Since we adopted a technique of preclotting the prosthesis with whole blood or albumin plus autoclaving and abandoned the inclusion technique, the reoperation rate has declined substantially. At 5 years, the actuarial freedom from reoperation for any reason on the ascending aorta or aortic valve for the 24 patients in whom this modification was used was 90% and for the remaining 103 patients, 73% (p = 0.17). No reoperations for pseudoaneurysms or technical problems were required in these 24 patients, whereas 10 reoperations for these complications were necessary in the other patients. The mean duration of follow-up was 54 months. The actuarial survival rate at 7 years for the entire group was 65%; for the patients with annuloaortic ectasia, 70%; for those with aortic dissection, 61%; for the patients with the Marfan syndrome, 57%. Actuarial freedom from operation on the remainder of the aorta at 7 years was 89%, but it was 78% for the subgroup with the Marfan syndrome. The satisfactory results with extended follow-up support the continued use of the composite graft technique as the preferred method of treatment for patients with annuloaortic ectasia or recurrent aneurysms of the sinuses of Valsalva and for patients with aortic dissection who require aortic valve replacement.

Management during reoperation of aortocoronary saphenous vein grafts with minimal atherosclerosis by angiography

The proper management of saphenous vein grafts showing minimal angiographic evidence of atherosclerosis at the time of reoperation for progressive atherosclerosis in the native coronary circulation or for severe atherosclerosis in other saphenous vein grafts is uncertain. Following the occlusion of vein grafts in 2 patients 7 and 12 years after operation but only 2 years after arteriography demonstrated no major abnormalities in the grafts, we adopted a policy of elective replacement of all saphenous vein grafts, irrespective of angiographic findings, when reoperation was necessary 5 or more years after the initial operation. Between July, 1984, and May, 1985, 16 patients had repeat coronary artery bypass grafting 6 to 13 years (mean, 9 years) after the initial procedure. Complete revascularization was carried out in all patients. In each, it included replacement of at least 1 saphenous vein graft showing no severe obstruction (less than 30% of the luminal diameter) and no (5 patients), minimal (8), or moderate (3) luminal irregularities by angiography. By pathological examination, 3 of the grafts had minimal, 5 had moderate, and 8 had severe atherosclerotic changes present. These changes were generally more diffuse than those observed by angiography. Because angiography underestimates the severity of the atherosclerotic degeneration in saphenous vein grafts and because of the propensity of the atherosclerotic disease to progress at an unpredictable rate, we recommend routine replacement of all saphenous vein grafts at the time of reoperation if done 5 or more years after the initial procedure.

Combined bipolar dual chamber pacing and automatic implantable cardioverter/defibrillator

A 67 year old man with recurrent hypotensive ventricular tachycardia, amiodarone-induced bradyarrhythmias and severe cardiac dysfunction underwent simultaneous implantation of an automatic cardioverter/defibrillator and bipolar atrioventricular (AV) pacemaker. The pacing electrodes were placed epicardially near the right atrial appendage and on the lateral right ventricular wall. The rate detector of the automatic defibrillator was placed epicardially on the posterobasal left ventricular wall. Effective bipolar AV pacing produced no false counting of the heart rate by the automatic cardioverter/defibrillator, and ventricular tachycardia properly inhibited the pacemaker. Long-term follow-up study confirmed the safety of this treatment. With proper precautions, bipolar AV pacing can be safely combined with an automatic cardioverter/defibrillator.