Floyd D. Loop

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.

Two internal thoracic artery grafts are better than one

OBJECTIVE Does the use of bilateral internal thoracic artery (ITA) grafts provide incremental benefit relative to the use of a single ITA graft? METHODS We conducted a retrospective, nonrandomized, long-term (mean follow-up interval of 10 postoperative years) study of patients undergoing elective primary isolated coronary bypass surgery who received either single (8123 patients) or bilateral ITA grafts (2001 patients), with or without additional vein grafts. Multiple statistical methods including propensity score matching, and multivariable parsimonious and nonparsimonious risk factor analyses were used to address the issues of patient selection and heterogeneity. RESULTS In-hospital mortality was 0.7% for both the bilateral and single ITA groups. Survival for the bilateral ITA group was 94%, 84%, and 67%, and for the single ITA group 92%, 79%, and 64% at 5, 10, and 15 postoperative years, respectively (P <.001). Death, reoperation, and percutaneous transluminal coronary angioplasty were more frequent for patients undergoing single rather than bilateral ITA grafting, and this observation remained true despite multiple adjustments for patient selection, sampling, and length of follow-up. The differences between the bilateral and single ITA groups were greatest in regard to reoperation. The extent of benefit of bilateral ITA grafting varied according to patient-related variables, but no patient subsets were identified for whom single ITA grafting could be predicted to provide an advantage. CONCLUSIONS Patients who received 2 ITA grafts had decreased risks of death, reoperation, and angioplasty.

Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting

Objective:Our objective was to quantify incremental risk associated with transfusion of packed red blood cells and other blood components on morbidity after coronary artery bypass grafting. Design:The study design was an observational cohort study. Setting:This investigation took place at a large tertiary care referral center. Patients:A total of 11,963 patients who underwent isolated coronary artery bypass from January 1, 1995, through July 1, 2002. Interventions:None. Measurements and Main Results:Among the 11,963 patients who underwent isolated coronary artery bypass grafting, 5,814 (48.6%) were transfused. Risk-adjusted probability of developing in-hospital mortality and morbidity as a function of red blood cell and blood-component transfusion was modeled using logistic regression. Transfusion of red blood cells was associated with a risk-adjusted increased risk for every postoperative morbid event: mortality (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.67–1.87; p < .0001), renal failure (OR, 2.06; 95% CI, 1.87–2.27; p < .0001), prolonged ventilatory support (OR, 1.79; 95% CI, 1.72–1.86; p < .0001), serious infection (OR, 1.76; 95% CI, 1.68–1.84; p < .0001), cardiac complications (OR, 1.55; 95% CI, 1.47–1.63; p < .0001), and neurologic events (OR, 1.37; 95% CI, 1.30–1.44; p < .0001). Conclusions:Perioperative red blood cell transfusion is the single factor most reliably associated with increased risk of postoperative morbid events after isolated coronary artery bypass grafting. Each unit of red cells transfused is associated with incrementally increased risk for adverse outcome.

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.

Durability of mitral valve repair for degenerative disease

BACKGROUND Degenerative mitral valve disease is the most common cause of mitral regurgitation in the United States. Mitral valve repair is applicable in the majority of these patients and has become the procedure of choice. OBJECTIVE This study was undertaken to identify factors influencing the durability of mitral valve repair. PATIENTS AND METHODS Between 1985 and 1997, 1072 patients underwent primary isolated mitral valve repair for valvular regurgitation caused by degenerative disease. Repair durability was assessed by multivariable risk factor analysis of reoperation. It was supplemented by a search for valve-related risk factors for death before reoperation. Three hospital deaths occurred (0.3%); complete follow-up (4152 patient-years) was available in 1062 of 1069 hospital survivors (99.3%). RESULTS At 10 years, freedom from reoperation was 93%. Among 30 patients who required reoperation for late mitral valve dysfunction, the repair failed in 16 (53%) as a result of progressive degenerative disease. Durability of repair was adversely affected by pathologic conditions other than posterior leaflet prolapse, use of chordal shortening, annuloplasty alone, and posterior leaflet resection without annuloplasty. Durability was greatest after quadrangular resection and annuloplasty for posterior leaflet prolapse and was enhanced by the use of intraoperative echocardiography. Death before reoperation was increased in patients having isolated anterior leaflet prolapse or valvular calcification and by use of chordal shortening or annuloplasty alone. CONCLUSIONS Repair durability is greatest in patients with isolated posterior leaflet prolapse who have posterior leaflet resection and annuloplasty. Chordal shortening, annuloplasty alone, and leaflet resection without annuloplasty jeopardize late results.

Role of prophylactic anticoagulation for direct current cardioversion in patients with atrial fibrillation or atrial flutter

The need for prophylactic anticoagulation to prevent embolism before direct current cardioversion is performed for atrial fibrillation or atrial flutter is controversial. To examine this issue further, a retrospective review was undertaken to assess the incidence of embolic complications after cardioversion. The review involved 454 elective direct current cardioversions performed for atrial fibrillation or atrial flutter over a 7 year period. The incidence rate of embolic complications was 1.32% (six patients); the complications ranged from minor visual disturbances to a fatal cerebrovascular event. All six patients had atrial fibrillation, and none had been on anticoagulant therapy (p = 0.026). The duration of atrial fibrillation was less than 1 week in five of the six patients who had embolic complications. Baseline characteristics of patients with a postcardioversion embolic event are compared with those of patients who did not have an embolic event. There was no difference in the prevalence of hypertension, diabetes mellitus or prior stroke between the two groups, and there was no difference in the number of patients who were postoperative or had poor left ventricular function. Left atrial size was similar between the two groups. No patient in the embolic group had valvular disease. No patient with atrial flutter had an embolic event regardless of anticoagulant status; therefore, anticoagulation is not recommended for patients with atrial flutter undergoing cardioversion. Prophylactic anticoagulation is pivotal in patients undergoing elective direct current cardioversion for atrial fibrillation, even those with atrial fibrillation of less than 1 weeks duration.

Coronary artery surgery in women compared with men: Analyses of risks and long-term results

A surgical experience with 2,445 consecutive women who underwent isolated bypass grafting was analyzed for comparison with 18,079 consecutive men. Severe or unstable angina occurred preoperatively in 60% of women and 45% of men (p less than 0.001). Despite less three vessel disease (44 versus 56%, p less than 0.001) and better left ventricular contraction (normal in 60% of women and 53% of men [p less than 0.001]), women had a higher operative mortality rate (2.9 versus 1.3%). When matched for age, severity of angina and extent of coronary atherosclerosis, women still had twice the operative mortality of men. In matched patients, body surface area was the strongest predictor of operative risk, even when the model was adjusted for gender. When the model was adjusted for body surface area, gender was not an important predictor of operative death. The smaller size of women, rather than their sex, appears to explain the difference in operative mortality. After a mean interval of 2 years, women had a lower overall graft patency rate (76.4%) than men (82.1%) (p less than 0.001). At 5 and 10 years postoperatively, a higher percent of men were angina-free. Yet, survival for women (90.6%) and for men (93.0%) at 5 years, and at 10 years (78.6 and 78.2%, respectively) was not dissimilar.

Outmigration For Coronary Bypass Surgery in an Era of Public Dissemination of Clinical Outcomes

BACKGROUND Since 1989, New York State has disseminated comparative information on outcomes of coronary bypass surgery to the public. It has been suggested that this program played a significant role in the 41% decrease in the risk-adjusted mortality rate between 1989 and 1992. We hypothesized that some high-risk patients had migrated out of state for surgery. METHODS AND RESULTS We reviewed 9442 isolated coronary bypass operations performed from 1989 through 1993 to assess referral patterns of case-mix and outcome. Expected and risk-adjusted mortality rates were computed using logistic regression models derived from the Cleveland Clinic and New York State databases. A mortality comparison was performed using the 1980 to 1988 time period as a historical control. Patients from New York (n=482) had a higher frequency of prior open heart surgery (44.0%) than patients from Ohio (n=6046) (21.5%, P<.001), other states (n=1923) (37.4%, P=.008), and other countries (n=991) (17.3%, P<.001). They were also more likely to be in NYHA functional class III or IV (47.6% versus Ohio 42.7%, P=.037; other states, 41.2%, P=.011; other countries, 34.1%, P=.001). The expected mortality rate was thus higher than among other referral cohorts. The observed 5.2% mortality rate among these patients was significantly greater than the 2.9%, 3.1%, and 1.4% mortality rates observed for patients from Ohio (P=.004), other states (P=.028), and other countries (P<.001). These differences in outcome were not apparent between 1980 and 1988 among referrals from within the United States. CONCLUSIONS Public dissemination of outcome data may have been associated with increased referral of high-risk patients from New York to an out-of-state regional medical center.

Determinants of Blood Utilization during Myocardial Revascularization

Blood transfusion during cardiac surgical procedures has steadily decreased, but little information is available regarding the factors that determine its necessity or amount. To determine the predictors of blood utilization during myocardial revascularization, 441 consecutive patients undergoing primary myocardial revascularization were studied. Forty-four patients (10%) received blood during hospitalization with a mean transfusion of 0.3 +/- 1.4 units per patient. Age, sex, weight, body surface area, preoperative hematocrit, blood volume, and red blood cell volume were examined univariately for trends. All demonstrated a statistically significant trend for both need and amount of transfusion (p less than 0.001). Neither number of grafts nor duration of cardiopulmonary bypass demonstrated statistically significant trends. All univariately significant factors were evaluated by multivariate logistic regression analysis. Red cell volume was the best predictor of the need for transfusion (p less than 0.001), followed by age. No other factors improved predictive capabilities. We conclude that preoperative red cell mass and age are the principal determinants of the need for and quantity of blood transfused during myocardial revascularization. Use of this information may greatly improve the efficiency of ordering blood before operation.

Surgical treatment of prosthetic valve endocarditis

Despite advances in the diagnosis and treatment of prosthetic valve endocarditis (PVE) it remains a serious complication of prosthetic valve replacement. Antibiotic treatment alone can be successful for late infections that involve the prosthesis only (particularly for patients with bioprothesis), but it rarely cures infections involving the valve-native annulus interface. Combined antibiotic and surgical treatment of PVE often is successful; more accurate diagnosis (usually based on echocardiography), more effective myocardial protection at reoperation, and improved surgical experience have improved the short-term and long-term outcomes for patients with PVE. For 146 patients of Cleveland Clinic Foundation who underwent reoperation for PVE from 1975 through 1992, the overall in-hospital mortality rate was 13%, 10% from 1985 to 1992. In this more recent surgical period, active infection and early PVE did not appear to be factors that increase in-hospital mortality. The mean in-hospital stay of survivors was 25 days, which highlights the fact that even successful treatment of PVE uses enormous resources. The late survival rate of in-hospital survivors was 82% at 5 years, and the reoperation-free survival rate was 75% at 5 postoperative years.