Leonard A.R. Golding

Influence of the Internal-Mammary-Artery Graft on 10-Year Survival and Other Cardiac Events

We compared patients who received an internal-mammary-artery graft to the anterior descending coronary artery alone or combined with one or more saphenous-vein grafts (n = 2306) with patients who had only saphenous-vein bypass grafts (n = 3625). The 10-year actuarial survival rate among the group receiving the internal-mammary-artery graft, as compared with the group who received the vein grafts (exclusive of hospital deaths), was 93.4 percent versus 88.0 percent (P = 0.05) for those with one-vessel disease; 90.0 percent versus 79.5 percent (P less than 0.0001) for those with two-vessel disease; and 82.6 percent versus 71.0 percent (P less than 0.0001) for those with three-vessel disease. After an adjustment for demographic and clinical differences by Cox multivariate analysis, we found that patients who had only vein grafts had a 1.61 times greater risk of death throughout the 10 years, as compared with those who received an internal-mammary-artery graft. In addition, patients who received only vein grafts had 1.41 times the risk of late myocardial infarction (P less than 0.0001), 1.25 times the risk of hospitalization for cardiac events (P less than 0.0001), 2.00 times the risk of cardiac reoperation (P less than 0.0001), and 1.27 times the risk of all late cardiac events (P less than 0.0001), as compared with patients who received internal-mammary-artery grafts. Internal-mammary-artery grafting for lesions of the anterior descending coronary artery is preferable whenever indicated and technically feasible.

Sternal wound complications after isolated coronary artery bypass grafting: Early and late mortality, morbidity, and cost of care ☆

Of 6,504 consecutive patients who underwent isolated coronary bypass grafting in 1985 to 1987, 72 (1.1%) patients experienced sternal wound complications. Ten patients (14%) with wound complications died of multi-system failure. Only the patients with negative cultures fared well; of the bacterial culture categories, polymicrobial infection carried the worst prognosis. Effects of recurring infection were seen throughout the first year. Patients, grouped according to conduits received, experienced these wound complication rates: vein grafts only, 11/1,085 (1.0%); one internal thoracic artery, 38/4,073 (0.9%); and bilateral internal thoracic artery grafts, 23/1,346 (1.7%). There were no significant differences in wound complication rates between primary and reoperation patients or among conduit groups. By logistic regression analysis, the relative risk for patients with diabetes and bilateral internal thoracic artery grafting was 5.00 (95% confidence interval, 2.4 to 10.5). Operation time as a continuous variable increased the relative risk of wound complication 1.47 times per hour (1.3 to 1.7); obesity, 2.90 times (1.8 to 4.8); and blood units as continuous variable, 1.05 times per unit (1.01 to 1.10). Bilateral internal thoracic artery grafting in nondiabetic patients carried no greater risk of wound complication than that in patients with vein grafts only or with one internal thoracic artery graft.

Aprotinin therapy for reoperative myocardial revascularization: A placebo-controlled study

We tested the efficacy and safety of aprotinin in 169 patients undergoing isolated reoperative myocardial revascularization. Patients were randomly assigned to high-dose aprotinin, low-dose aprotinin, or placebo treatment groups in a double-blind, placebo-controlled study. Treatment groups did not differ significantly with respect to age, sex, red cell mass, number of grafts, use of internal thoracic artery, or incidence of preoperative aspirin therapy. Patients treated with aprotinin had a significant reduction in postoperative chest tube drainage (720 +/- 753, 866 +/- 1,636, and 1,121 +/- 683 mL, respectively, for high-dose aprotinin, low-dose aprotinin, and placebo; p < 0.001). Transfusion requirements were reduced in aprotinin-treated patients (2.1 +/- 4.2, 4.8 +/- 11.8, and 4.1 +/- 6.2 units for high-dose, low-dose, and placebo, respectively; p < 0.001). A similar reduction in chest tube drainage and transfusion requirements was seen in patients using aspirin preoperatively. Q-wave myocardial infarctions were increased in the aprotinin subgroups (17.5%, 14.3%, and 8.9% for high-dose, low-dose, and placebo groups; not significant). Acute vein graft thrombosis was found in six of 12 vein grafts studied at postmortem examination in patients receiving aprotinin but not in any of five grafts in patients receiving placebo. We conclude that aprotinin is extremely effective in reducing bleeding and transfusion requirements and may increase the risk of graft thrombosis.

Reoperation for Coronary Atherosclerosis: Changing Practice in 2509 Consecutive Patients

We analyzed trends in clinical, angiographic, and operative variables and documented long-term survival in 2509 consecutive patients who underwent reoperation for myocardial revascularization at The Cleveland Clinic during a 20-year period (1967 to 1987). The patients were grouped into four cohorts by year of surgery. This analysis showed that vein graft atherosclerosis has become the leading indication for reoperation, and patient age and interval between operations continue to increase. Mortality rates ranged from 2% to 5% and, despite increasing comorbidity, more extensive coronary atherosclerosis, and worse left ventricular function, the hospital mortality rate was 2.9% from 1985 to 1987. Perioperative new Q-wave myocardial infarction occurred in 7% to 8% of patients from 1967 to 1984 but decreased to 4% in the 1985 to 1987 period (p = 0.04). Internal thoracic artery graft usage in reoperations increased from 27% in the 1967 to 1978 period to 67% in the 1985 to 1987 period. Advanced age and presence of left main coronary artery disease adversely influenced late survival more consistently than other factors. Patients operated on in 1967 to 1978 had fewer risk factors, which explains their higher survival rate compared with more recent cohorts. Factors associated with improved 10-years actuarial survival included age younger than 65 years, mild angina, no major comorbidity, no left main coronary artery disease, good left ventricular performance, and an internal thoracic artery graft.

Treatment of cardiogenic shock with the hemopump left ventricular assist device

A multiinstitutional study is in progress to evaluate the Hemopump in the treatment of cardiogenic shock. Fifty-three patients with refractory cardiogenic shock were selected for Hemopump assistance. The hemodynamic definition of cardiogenic shock included (1) a cardiac index of less than 2.0 L.min-1.m-2, (2) pulmonary capillary wedge pressure of greater than 18 mm Hg, and (3) a systolic blood pressure of less than 90 mm Hg or a left ventricular work index of less than 1,500 g-m.m-2.min-1. The Hemopump was successfully inserted in 41 of 53 patients (77.3%). A significant improvement in the hemodynamic status was seen during Hemopump assistance. A minimal level of hemolysis was observed. No leg ischemia was observed. The 30-day overall survival of the Hemopump group was 31.7%. Criteria establishing indications for use and clinical utility are proposed. We conclude that the Hemopump provides significant hemodynamic support of the patient in cardiogenic shock allowing for recovery from ventricular stunning in marginal ventricles, and that in select patients the Hemopump may offer a major improvement in survival over conventional therapy.

Replacement of aortic valve combined with myocardial revascularization: determinants of early and late risk for 500 patients, 1967-1981.

Five hundred consecutive patients underwent aortic valve replacement and coronary revascularization in the years from 1967 to 1981, with 29 (5.9%) in-hospital deaths. Current operative mortality (1978-1981) is 3.4%. Univariate and multivariate analyses were used to identify determinants of early and late risk. Female sex, aortic insufficiency, and advanced age increased in-hospital mortality, whereas use of cardioplegia decreased it. At follow-up of 471 patients who survived hospitalization for 1 to 135 months (mean 41) after surgery, 96 late deaths were documented. Survival rates were 87%, 80%, and 55%, and event-free survival rates were 80%, 65%, and 39% at 2, 5, and 10 years after surgery, respectively. The late survival rate was unfavorably influenced by the presence of moderately or severely impaired left ventricular function and double-vessel coronary disease; the rate was enhanced for patients in age group from 50 to 59 years old and was not influenced by the method of myocardial protection. The event-free survival rate decreased with the presence of moderately or severely impaired left ventricular function and was enhanced for patients with New York Heart Association class I or II symptoms before surgery. Patients with bioprostheses who did not receive anticoagulants had higher survival and event-free survival rates than did either patients with bioprostheses who received anticoagulants or patients with mechanical valves, whether they received anticoagulants or not.

Trends in Selection and Results of Coronary Artery Reoperations

The first 1,000 patients undergoing isolated coronary artery reoperation were divided into four cohorts of 250 patients each: 1969 to 1976; 1976 to 1979; 1979 to 1981; and 1981 into 1982. Graft failure as an indication for reoperation rose from 26% in Group 1 to 40% in Group 4, and the interval lengthened from 17 to 61 months, presumably a result of late closures 5 to 10 years postoperatively. Progressive atherosclerosis in previously ungrafted vessels has decreased from 62% in Group 1 to 23% in Group 4, a decline attributed to more complete revascularization initially. The frequency of three-vessel disease, stenosis of the left main coronary artery, and left ventricular impairment continues to rise in candidates for reoperation. Yet, operative mortality has declined from 5% to 2%, and most other forms of perioperative morbidity have decreased significantly when the early years are compared with the later experience. The number of grafts per patient has increased from 1.4 to 2.3, and complete revascularization in reoperations has increased from 65% to 76%. After a mean of 29 months, graft patency was 81% overall in 154 patients restudied after reoperation. Patency was similar for grafts to arteries previously involved with graft failure and to arteries not previously grafted. Five-year actuarial survival for patients in the first three cohorts (mean, 57 months) was 89%.(ABSTRACT TRUNCATED AT 250 WORDS)

Postcardiotomy centrifugal mechanical ventricular support

From August 1979 through August 1991, 91 patients were supported with centrifugal mechanical ventricular assist. Major indications for its use were postcardiotomy ventricular failure (79) or as a bridge to cardiac transplantation (12). In postcardiotomy use (0.2% of all cardiac procedures), there were 54 male (68.4%) and 25 female patients (31.6%) with a mean age of 54.8 years and a mean duration of use of 3.56 days (range, 1 hour to 19 days). Forty-nine patients (62%) were successfully weaned, and 20 (25.3%) were hospital survivors. In 57 patients the device was inserted to wean from cardiopulmonary bypass, whereas in 22 it was employed later in the postoperative period because of low cardiac output or sudden arrest. Thirty-four (59.6%) of the 57 patients in the former group were weaned, and 15 (26.3%) were discharged, results similar to those in the latter group with 15 (68.2%) weaned and 5 (22.7%) discharged. Morbidity associated with use of centrifugal blood pumps included bleeding (87.3%; mean transfusion requirement, 53.2 units), renal failure (46.8%), cerebrovascular accident (12.7%), thromboembolism (12.7%), and hepatic insufficiency (12.7%). After a mean follow-up of 45.4 months (range, 2 to 142 months), 7 patients had died (35% late mortality), 1 patient is in functional class IV, and all others are in functional class I or II. Lower survival was associated with biventricular failure and renal failure but not with age or sex of the patient.

Determinants of 10-year survival after primary myocardial revascularization.

The first 1000 patients undergoing primary isolated myocardial revascularization each year from 1971 to 1978 were analyzed to elucidate the determinants of long-term survival. Five-year survival was 93.2%, and 10-year survival was 79.3%. Five-year survivals were 96.1%, 94.2%, 92.1%, and 90.8%, respectively, for single, double, triple, and left main disease. Ten-year survivals for the same subsets were 88.6%, 83.0%, 74.9%, and 70.9%. Five-year survivals were 95.3%, 92.4%, 88.0%, and 81.3% for patients with normal, mild, moderate, and severe impairment of the left ventricle. Ten-year survivals for the same subsets were 84.1%, 76.5%, 65.8% and 53.6%. Patients receiving internal mammary artery grafts had 95.6% and 85.8% 5- and 10-year survivals that were superior to 92.0% and 76.2% in patients with only vein grafts. Patients completely revascularized had 95.0% and 82.5% 5- and 10-year survivals, while incompletely revascularized patients had lower (90.5% and 75.2%) 5- and 10-year survivals. Advancing age was the most important factor influencing late survival. Other risk factors in descending order of significance were impaired left ventricular function, no mammary artery graft, smoking, abnormal EKG, three vessel or left main disease, left ventricular end diastolic pressure (LVEDP) greater than 24, hypertension, 1971 to 1974 surgical era, cholesterol greater than 300, incomplete revascularization, and two vessel disease.

AN INNOVATIVE, SENSORLESS, PULSATILE, CONTINUOUS-FLOW TOTAL ARTIFICIAL HEART: DEVICE DESIGN AND INITIAL IN VITRO STUDY

BACKGROUND We are developing a very small, innovative, continuous-flow total artificial heart (CFTAH) that passively self-balances left and right pump flows and atrial pressures without sensors. This report details the CFTAH design concept and our initial in vitro data. METHODS System performance of the CFTAH was evaluated using a mock circulatory loop to determine the range of systemic and pulmonary vascular resistance (SVR and PVR) levels over which the design goal of a maximum absolute atrial pressure difference of 10 mm Hg is achieved for a steady-state flow condition. Pump speed was then modulated at 2,600 +/- 900 rpm to induce flow and arterial pressure pulsation to evaluate the effects of speed pulsations on the system performance. An automatic control mode was also evaluated. RESULTS Using only passive self-regulation, pump flows were balanced and absolute atrial pressure differences were maintained at <10 mm Hg over a range of SVR (750 to 2,750 dyne.sec.cm(-5)) and PVR (135 to 600 dyne.sec.cm(-5)) values far exceeding normal levels. The magnitude of induced speed pulsatility affected relative left/right performance, allowing for an additional active control to improve balanced flow and pressure. The automatic control mode adjusted pump speed to achieve targeted pump flows based on sensorless calculations of SVR and CFTAH flow. CONCLUSIONS The initial in vitro testing of the CFTAH with a single, valveless, continuous-flow pump demonstrated its passive self-regulation of flows and atrial pressures and a new automatic control mode.