The changing mortality of myocardial revascularization: coronary artery bypass and angioplasty

A simultaneous coronary artery bypass grafting on beating heart and right upper lobectomy in a patient with a lung adenocarcinoma

A coexisting coronary heart disease may increase the operative mortality and morbidity rates of lung resection. A simultaneous or a two-stage procedure using myocardial revascularization prior to the pulmonary resection may reduce the postoperative morbidity and mortality. Herein, we present a 65-year-old male case of a lung adenocarcinoma in whom a simultaneous coronary artery bypass grafting on a beating heart and right upper lobectomy was performed.

Factors affecting postoperative morbidity and mortality in isolated coronary artery bypass graft surgery

PURPOSE

This study was conducted to investigate predictors of mortality before and after isolated coronary artery bypass grafting (CABG).

METHODS

Single-institutional data on risk factors and mortality were collected for 8890 patients who underwent isolated CABG by the same group of surgeons. The relationship between risk factors and outcome was assessed using univariate and multivariate analyses in two risk models: a preoperative model (model 1) and then a pre-, intra-, and postoperative model (model 2).

RESULTS

The mean age of the patients (25.4% women and 74.6% men) was 58.5 +/- 9.7 years. Fifty-five (0.6%) patients died after surgery. Hypercholesterolemia was the most common comorbidity factor (61.1%), followed by hypertension, a smoking habit, recent myocardial infarction (MI) <21 days, and diabetes. Postoperative tamponade, graft occlusion, and MI (0.01%) were the least common complications. The patients spent 39.7 +/- 33.9 h in the intensive care unit (ICU) postoperatively. Patients were followed up for a minimum of 30 days. The multivariate analysis of our preoperative risk model revealed that the best predictors of operative mortality were a history of diabetes, hypertension, previous CABG, the presence of angina, arrhythmia, Canadian Cardiovascular Society Classification (CCS) of grade III or IV, ejection fraction (EF) < or =30%, three-vessel disease, and left main disease.

CONCLUSION

After surgery, and with the inclusion of all the pre-, intra-, and postoperative variables into model two, the following were revealed to be prognostic factors for in-hospital mortality: a history of diabetes, hypertension, the presence of angina, CCS grades III or IV, EF -30%, absence of internal mammary artery (IMA) use, prolonged cardiopulmonary bypass (CPB) time, and prolonged ICU stay.

Effect of pexelizumab in coronary artery bypass graft surgery with extended aortic cross-clamp time

BACKGROUND

Prolonged cross-clamp time during cardiac surgery increases the risk of postoperative mortality and myocardial injury. This subanalysis from the pexelizumab for reduction of infarction and mortality in coronary artery bypass grafting surgery (PRIMO-CABG) trial, a phase III double-blind, placebo-controlled study of 3,099 patients undergoing on-pump coronary artery bypass graft surgery with or without valve surgery, assessed the impact of pexelizumab, an investigational C5 complement inhibitor, on postoperative outcomes after prolonged aortic cross-clamp time.

METHODS

The composite endpoint of death or myocardial infarction through postoperative day 30 and death alone through days 30, 90, and 180 were examined in subpopulations of patients across different cross-clamp times.

RESULTS

After prolonged cross-clamping (> or = 90 minutes), death, or myocardial infarction through day 30 and death through days 30, 90, and 180 were significantly increased in the intent-to-treat population and were even higher in patients with two or more prespecified risk factors, compared with all patients cross-clamped less than 90 minutes. Pexelizumab significantly reduced the incidence of death or myocardial infarction through day 30, and significantly reduced the incidence of mortality through day 180, in patients with two or more risk factors that required prolonged cross-clamp time. Pexelizumab also significantly reduced perioperative myocardial injury in all patients requiring prolonged cross-clamp time.

CONCLUSIONS

In this retrospective, subgroup analysis, pexelizumab reduced postoperative morbidity and myocardial injury in patients with multiple risk factors who underwent prolonged cross-clamp time during coronary artery bypass surgery. The clinical benefit of pexelizumab may be related to the effect of complement inhibition in the presence of potential ischemic-reperfusion injury associated with prolonged aortic cross-clamp time.

Combined left pneumonectomy and off-pump coronary artery bypass through left thoracotomy

Concomitant pneumonectomy and coronary artery bypass grafting (CABG) carry a high morbidity and mortality rate. We present the case of a patient operated on for left pneumonectomy and off pump CABG through a left thoracotomy incision in a one-stage procedure with a 1-year disease-free follow-up. To the best of our knowledge, simultaneous surgical management as presented in this patient has not been previously reported.

Determinants of hospital mortality after coronary artery bypass grafting

OBJECTIVES

To examine causes of death and to find predictors of hospital mortality after elective coronary artery bypass graft (CABG) surgery.

DESIGN

Case-control study.

SETTING

Tertiary teaching hospital.

METHODS

We prospectively collected various preoperative, operative, and immediate postoperative variables in a cohort of patients undergoing elective CABG surgery.

RESULTS

Of the 2,014 consecutive patients (mean [+/- SD] age of 61.3+/-6.7 years old) undergoing elective CABG over a 2-year period, 27 patients (1.3%) died during their hospitalization. The main causes of death (either isolated or in combination) were cardiogenic shock (n = 13), brain death or stroke (n = 7), septic shock (n = 4), ARDS (n = 2), and pulmonary embolism (n = 1). A univariate statistical analysis revealed factors that significantly correlate with outcome: patient age, preoperative left ventricular ejection fraction, bypass time, aortic cross-clamp time, number of blood units transfused, number of inotropic agents administered in the operating room during the first postoperative day (POD), history of arterial hypertension, intra-aortic balloon pump usage, and perioperative development of shock. A logistic regression analysis showed that the combination of the number of inotropes and the number of blood units administered in the operating room during POD 1 was the most important determinant of outcome, with an overall positive predictive value of 91.7%.

CONCLUSIONS

We conclude that the analysis of simple variables enhances our ability to accurately predict hospital mortality in patients undergoing elective CABG surgery. The number of inotropic agents and blood transfusions administered during the immediate postoperative period is the most important independent predictor of hospital mortality.

Impact of percutaneous transluminal coronary angioplasty on coronary bypass surgery--changes in the patient profile during the past decade

As percutaneous transluminal coronary angioplasty has become an increasingly common procedure replacing coronary artery bypass grafting (CABG), the clinical profile of the patients referred for CABG has changed markedly. A retrospective study of the changes in the clinical profile and surgical outcome of patients who underwent CABG during the past 10 years was conducted. Between March 1982 and February 1996, 1010 patients underwent isolated CABG at Nara Medical University. The first 100 consecutive patients who underwent CABG in 1984-85 (group 1) were compared with the first 100 consecutive patients who underwent CABG in 1994-95 (group 2). Preoperative risk increased significantly during the decade with respect to patient age (p<0.001), the presence of diabetes mellitus (p=0.048), the number of diseased vessels (p<0.001), left main trunk disease (p=0.008), the presence of aortic or peripheral vascular disease (p=0.032),and the need for emergency surgery (p=0.013). Operative procedures have become more complicated with respect to the number of total and arterial grafts, duration of the aortic cross-clamp and cardiopulmonary bypass. Hospital mortality for elective CABG has not changed (2%) and the overall mortality has not increased significantly (from 2% to 3%) during the decade. In conclusion, although the preoperative risks have increased and more complicated procedures are required, CABG continues to be performed safely with low mortality rates.

Influence of ascending versus descending balloon counterpulsation on bypass graft blood flow

BACKGROUND

Mechanical circulatory assistance is frequently needed in postcardiotomy patients to support the failing heart. A balloon catheter called SupraCor (ABIOMED Cardiovascular, Inc, Danvers, MA) has been developed and is similar to the existing intraaortic balloon pump with the exception of placement in the ascending versus the descending thoracic aorta. This investigation compared the effects of SupraCor versus standard intraaortic balloon pump on internal mammary artery and venous conduit bypass graft blood flow.

METHODS

Porcine total heart bypass was used to anastomose a jugular vein from the ascending aorta to a subsequently ligated left anterior descending coronary artery. The left internal mammary artery was then anastomosed to the jugular vein so each conduit perfused the same coronary vascular bed. An additional right heart bypass preparation allowed precise control of cardiac output and blood pressure, which were maintained constant throughout mechanical circulatory assistance. Electromagnetic flow probes measured flow through each bypass graft and the other conduit was atraumatically occluded.

RESULTS

The SupraCor caused a significant increase in both internal mammary artery (+70% from 35 +/- mL/min to 56 +/- 9 mL/min; p = 0.04) and venous bypass graft blood flow (+49% from 66 +/- 12 mL/min to 95 +/- 15 mL/min; p = 0.02) when compared with controls. The intraaortic balloon pump failed to alter internal mammary artery or venous bypass graft flow.

CONCLUSIONS

The results demonstrate that counterpulsation with an ascending aortic balloon significantly increases coronary bypass graft flow in both internal mammary artery and venous conduits. In contrast, counterpulsation with a descending aortic balloon did not alter coronary bypass graft flow.

North American experience with the Perma-Flow prosthetic coronary graft

BACKGROUND

The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives.

METHODS

Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study.

RESULTS

Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 +/- 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft.

CONCLUSIONS

The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.

CABG after successful PTCA: a case-control study

We sought characteristics predictive of the need for operative revascularization subsequent to a successful coronary angioplasty. Through June 1993, 128 patients who had successful percutaneous transluminal coronary angioplasty (PTCA) between January 1982 and March 1989 required subsequent coronary artery bypass grafting (CABG) at our hospital. These cases were matched with 128 controls who had a successful PTCA but did not require subsequent CABG. Controls were matched to cases by the date of their initial PTCA. Before initial PTCA there were no differences between the cases and controls in terms of age, sex, prior myocardial infarction, ejection fraction, duration of anginal symptoms, hypertension, hyperlipidemia, family history, or obesity (all not significant). A greater number of cases had diabetes (35 versus 18; p = 0.009). Angiography before initial PTCA revealed that cases had a greater mean number of total lesions (4.1 versus 3.3; p = 0.002) and a higher incidence of left anterior descending and circumflex artery stenoses of 70% or greater (98 versus 75 and 57 versus 34, respectively; p = 0.006). The mean number of lesions successfully dilated was greater in cases (2.4 versus 1.7; p = 0.0001). Cases had CABG at a mean interval of 16.7 +/- 23 months. There were 17 late deaths among cases and 9 among the controls at a mean of 38.6 +/- 30 months. The survival probability at 5 years was 94.5% for controls and 87.9% for cases (p = 0.048). Initial revascularization by PTCA is followed by CABG at a brief interval in a subset of patients who have markers of more severe disease than do patients who do not require early CABG.(ABSTRACT TRUNCATED AT 250 WORDS)

Vascular complications from intraaortic balloons: risk analysis

PURPOSE

The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support.

METHODS

Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution.

RESULTS

Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived.

CONCLUSIONS

Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

Coronary artery bypass grafting in patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a disease of the elderly. It tends to have a variable clinical course. Because of the patients' immunologically dysfunctional state, there has been reluctance to perform open cardiac procedures because of concern about early postoperative sepsis leading to death. To assess the risk of coronary artery bypass grafting in elderly patients, the records of 26 patients (mean age, 69.6 +/- 4.9 years) with chronic lymphocytic leukemia who underwent coronary artery bypass grafting between January 1975 and July 1990 were retrospectively reviewed. Nineteen underwent isolated coronary artery bypass grafting, and 7 had combined procedures. The operative mortality rate was 7.7%. Postoperative infections developed in 6 patients (23.1%): pneumonia in 3 and sternal osteomyelitis, acute parotiditis, and bacteremia in 1 each. One of these 6 patients died of acute Serratia pneumonitis. Twenty-four patients (92.3%) were discharged from the hospital an average of 10.6 +/- 7.7 days postoperatively. Patients with chronic lymphocytic leukemia can undergo coronary artery bypass grafting with acceptable mortality but with increased risk of postoperative infection.

Myocardial revascularization. Coronary angioplasty and bypass surgery indications

Coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) have been performed increasingly over the last 20 and 10 years, respectively. The growth in PTCA is both complementary and threatening to CABG. The controversy between cardiologists and cardiac surgeons over the role of each procedure will no doubt continue as new devices are developed for coronary interventions. This article reviews the controversy and provides information to internists so that they will be fully prepared to advise patients about their treatment options.

Risk factors for pancreatic cellular injury after cardiopulmonary bypass

BACKGROUND

Pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass. Although ischemia is believed to be a factor, the cause of pancreatitis after cardiopulmonary bypass remains unknown.

METHODS

We prospectively studied 300 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. Serum amylase, pancreatic isoamylase, and serum lipase were measured on postoperative days 1,2,3,7, and 10. Pancreatic cellular injury was defined as the presence of hyperamylasemia (greater than 123 U per liter) with an increase in either the serum level of lipase (greater than 24 U per liter) or the peak level of pancreatic isoamylase. Trypsinogen-activation peptides, which indicate intrapancreatic enzyme activation, were measured in the urine of the last 101 patients studied.

RESULTS

Evidence of pancreatic cellular injury was detected in 80 patients (27 percent), of whom 23 had associated abdominal signs or symptoms and 3 had severe pancreatitis (2 with pancreatic abscess and 1 with necrotizing hemorrhagic pancreatitis). Two of 19 postoperative deaths were secondary to pancreatitis. In multivariate analyses, the development of pancreatic cellular injury was significantly associated with preoperative renal insufficiency, valve surgery, postoperative hypotension, and perioperative administration of calcium chloride. The administration of more than 800 mg of calcium chloride per square meter of body-surface area was an independent predictor of pancreatic cellular injury, and the increase in risk was dose-related. No differences were found in the level of trypsinogen-activation peptides between patients who had pancreatic cellular injury and those who did not.

CONCLUSIONS

Pancreatic cellular injury, as indicated by hyperamylasemia of pancreatic origin, is common after cardiac surgery. The administration of large doses of calcium chloride is an independent predictor of pancreatic cellular injury and may be a cause of it.

Reoperation in the intensive care unit

From July 1, 1984, through June 30, 1989, after 1,259 open heart operations, 110 patients (8.7%) underwent 162 early reoperations either in the intensive care unit (144 procedures) or in the operating room (26 procedures). Reexploration for bleeding (49 procedures) (3.9%) and intraaortic balloon removal (50 procedures) (4.0%) were the two most common procedures. Ninety percent and 96% of these procedures, respectively, were performed in the intensive care unit. Mediastinal infections occurred in 4 (6.1%) of 66 patients undergoing repeat mediastinal operations for all indications. No infection occurred after reexploration for bleeding nor did mediastinal infection occur after reoperation in the intensive care unit. Postoperative death in these 110 patients was not related to reoperation except possibly in the case of 1 patient (0.9%). Average transit time to and from the operating room for patients returned there for reoperation was 89.7 minutes. Charges for procedures performed in the operating room were at least twice as great as for those performed in the intensive care unit. This experience supports expanded use of reoperation in the intensive care unit, as it is safe, effective, economical, and convenient.

Current status of cardiac surgery: a 40 year review

Cardiac surgery has undergone dramatic advancements during the past 3 decades. The introduction of cardiopulmonary bypass and cardioplegic arrest ushered in the true era of open heart surgery. Bioprostheses and mechanical valves as well as techniques for valve reconstruction permit routine repair or replacement of stenotic and regurgitant native valves. Progress in the disciplines of mechanical and electrical engineering has led to the development of pocket watch-sized, physiologically responsive pacemakers as well as a variety of circulatory assist devices that include the intraaortic balloon pump, ventricular assist device and total artificial heart. The synthesis of cardiotonic and vasoactive drugs and advancements in anesthetic management, postoperative monitoring and nursing care greatly facilitate perioperative patient management. This summary of state of the art cardiac surgery begins with a brief historical background followed by a review of recent advances in six main categories: coronary artery disease, acquired valvular heart disease, congenital cardiac disease, cardiac transplantation, myocardial preservation and mechanical circulatory assistance. In conducting the review of recent literature, particular attention was directed to large clinical series that document the results of contemporary surgical procedures, novel therapeutic approaches to current clinical problems and unresolved controversies in the field of cardiac surgery. The abundance of surgical literature and constraints on the length of this article do not permit an exhaustive review. Apologies are extended to clinicians and laboratory investigators whose important contributions to the understanding and treatment of cardiac disease are not included herein.

Emergency coronary artery bypass grafting for failed angioplasty: risk factors and outcome

It has been suggested that coronary artery bypass grafting (CABG) performed in the setting of emergent failure of percutaneous transluminal coronary angioplasty causes minimal increased risk compared with routine CABG. We reviewed the records of 103 patients undergoing emergency CABG for failed percutaneous transluminal coronary angioplasty (group 1) and compared them with an identical number of consecutive CABG patients from 1987 (group 2). Group 1 had a lower risk profile evidenced by lower mean age (p less than 0.01), fewer diseased vessels (p less than 0.0001), better ventricular function (p less than 0.001), fewer left main lesions (p less than 0.0001), and fewer patients with acute ischemia requiring intravenous administration of nitroglycerin (p less than 0.01). Despite these differences, the group 1 patients had a higher mortality rate (11% versus 1%; p less than 0.01) and a higher rate of perioperative infarctions (new Q wave) (22% versus 6%; p less than 0.01). An analysis of risk factors was performed in the group 1 patients using 36 preoperative and operative variables. Multivariate analysis revealed that left ventricular score (p less than 0.0001), preoperative (after percutaneous transluminal coronary angioplasty) need for inotropic support (p less than 0.005), and age (p less than 0.025) were independent predictors of operative mortality. In conclusion, emergency CABG after failed percutaneous transluminal coronary angioplasty carries a significantly greater risk of operative death and perioperative infarction than elective CABG.