Coronary bypass with ejection fraction of 0.20 or less using centigrade cardioplegia: long-term follow-up

Reoperative Total Arch Repair Using a Trifurcated Graft and Selective Antegrade Cerebral Perfusion

BACKGROUND

This study reviews the outcomes of our reoperative total arch repair (TAR) technique using a trifurcated graft and selective antegrade cerebral perfusion (SACP).

METHODS

Fifty patients underwent reoperative TAR from January 2005 to September 2020, with either a one-stage (N=9), or two-stage repair (N=41). The two-stage technique includes minimal dissection of the mediastinal structures, an arch-first technique using a trifurcated graft, and construction of a classical elephant trunk via a partial transverse incision distally in the old-graft or in the aorta just distal to the old graft.

RESULTS

The median age was 63 years. Chronic dissection was the most frequent indication (88%) and 98% had undergone a previous proximal aortic repair at a median interval of 3.0 years. The median cardiopulmonary bypass, myocardial ischemic, SACP, and lower body circulatory arrest times were 226, 103, 97, and 98 minutes, respectively. The minimum nasopharyngeal and bladder temperature were 16.5 °C, and 20.0 °C. Operative mortality was 2% and the incidence of stroke, and spinal cord injury (SCI) were 2%, and 0%. Stage II repair was performed in 37 patients (open: 33 patients, endovascular: 4 patients), with two mortalities and no SCI. The median duration between stage I and II was 63 days. Survival and aortic event free rates at 3 years were 88.4 ±4.9%, and 89.8 ±5.0%.

CONCLUSIONS

We report a reoperative TAR technique that minimizes dissection of the cardiac structures, simplifies the distal anastomosis, and protects vital organs, such as the brain, heart, and spinal cord.

Decision making and results of coronary artery bypass grafting for patients with poor left ventricular function

BACKGROUND

The aim of this study is to determine the results of coronary artery bypass surgery in patients with a low ejection fraction. Between January 2007 and January 2011, 3556 consecutive patients who underwent coronary artery bypass grafting at the Cardiovascular Surgery Clinic at Sifa University Hospital, Izmir, Turkey, were analyzed retrospectively.

METHODS

The patients were divided into 2 groups. Patients undergoing isolated first-time elective coronary bypass surgery were classified according to their preoperative ejection fraction; Patients in Group I had an ejection fraction between 20% and 35% with poor left ventricular function (n = 1246; 695 men and 551 women; mean age, 62.25 ± 5.72 years, range, 47-78 years). Control patients in Group II underwent elective coronary artery bypass grafting at the same time and had left ventricular ejection fraction between 36% and 49% (n = 2310; 1211 men and 1099 women; mean age, 61.83 ± 8.12 years, range, 41-81 years). The mean follow-up time for all patients was 24 ± 9.4 months (range, 12-48 months). Patients were followed postoperatively at the end of the first month and every 6 months. The left ventricular ejection fraction was assessed by transthoracic echocardiography.

RESULTS

The mean number of distal anastomoses, myocardial infarction, and mean age was not significantly different between the 2 groups; however, cross-clamp time was longer in Group I. Patient recovery time was significantly longer in Group I. Morbidity (14.5% in Group I versus 7.4% in Group II, P < .005) and mortality (1.76% versus 0.30%, P < .005) were higher in Group I. During late follow-up, the 2-year survival rate (85.1% versus 94.5%) and 2-year event-free rate (77.6% versus 86.9%) were significantly lower in Group I when compared to Group II. Postoperative left ventricular ejection fraction values were significantly superior in Group I compared to Group II.

CONCLUSION

Coronary artery bypass grafting can be safely performed in patients with low ejection fraction with minimal postoperative morbidity and mortality. The viable myocardium could be reliably determined by positron emission tomography. Low ejection fraction patients could greatly benefit from coronary bypass surgery regarding postoperative ejection fraction, increased long-term survival, improvement in New York Heart Association classification, and higher quality of life.

The Role of Right Ventricular Function in Mitral Valve Surgery

<p><b>Background:</b> An impaired right ventricular function is associated with a poor survival rate in patients with heart failure. Few investigations have analyzed the prognostic value of right ventricular function on the outcomes of mitral valve (MV) surgery. The objectives of this study were to define the effect of right ventricular function on postoperative outcomes after MV repair (MVP) or replacement (MVR).</p><p><b>Methods:</b> From September 2007 to February 2012, 335 consecutive patients underwent MVP or MVR at our institution. Preoperative transthoracic and transesophageal echocardiography (TEE) and postoperative TEE were used to define right ventricular function and MV performance. Preoperative right ventricular function was graded as normal to mild (grade 1-2) or as moderate to severe (grade 3-4). MV or tricuspid valve regurgitation was graded as non-trivial to mild (grade 0-2) or as moderate to severe (grade 3-4) preoperatively and postoperatively. Survival rate was evaluated at 1 year after surgery.</p><p><b>Results:</b> Of the 334 patients in the study, 280 patients showed a normal to a mildly impaired right ventricular function preoperatively (group 1). Fifty-four patients presented with moderate to severe right ventricular dysfunction (group 2). Patients with a compromised right ventricular function were more likely to undergo MVR (28.6% versus 53.7%, <i>P</i> <.001). The mean pulmonary artery pressure was 23.6 mm Hg in group 1 and 34 mm Hg in group 2 (<i>P</i> <.001). The left atrial diameter was 4.6 cm in group 1 and 5.3 cm in group 2 (<i>P</i> <.001). The 2 groups were not different with respect to operative mortality, but the patients in group 2 experienced more transfusion of blood products (588.4 mL versus 1180.6 mL, <i>P</i> <.001), longer intensive care unit stays (83.9 versus 149.6 hours, <i>P</i> <.001), and hospital stays (8.9 versus 12.8 days, <i>P</i> = .005). The rate of postoperative MV regurgitation was significantly higher in group 2 (1.8 versus 14.8%, <i>P</i> <.001). The overall 1-year survival rate was 92.5% in group 1 and 94.5% in group 2 (<i>P</i> = .59).</p><p><b>Conclusions:</b> This study has shown that a dysfunctional preoperative right ventricular function uses more resources and is associated with postoperative MV regurgitation, but it is not associated short- and mid-term mortality after MV surgery.</p>

Surgical coronary revascularization in severe left ventricular dysfunction

Surgical revascularization in patients with coronary artery disease and severe left ventricular dysfunction is a common practice and poses a surgical challenge. From September 2002 to May 2004, 50 patients (47 men and 3 women; mean age, 59 +/- 9 years) with a mean preoperative ejection fraction of 19.7% +/- 3.2% underwent surgical revascularization. The mean EuroSCORE was 7.2 +/- 3.4. Indications for surgery were congestive heart failure in 8 patients (16%), angina in 20 (40%), ventricular arrhythmias in 4 (8%), and critical left main stem disease in 12 (24%). Twenty-two patients (44%) had emergency surgery for critical anatomy and unstable symptoms. The number of grafts per patient was 3.7 +/- 0.8. Seventeen patients (34%) required intra-aortic balloon pump support, 16 (32%) needed pacing, and 48 (96%) had inotropic support postoperatively. Morbidity included re-operation for bleeding (2%), acute renal failure (10%), hemodialysis (4%), and fatal multiorgan failure (4%). Postoperative (4.9 +/- 3.7 months) 2-dimentional echocardiography was available in 18 patients of whom 11 (61%) showed improved left ventricular function (range, 5% to 45%). Thirty-day hospital mortality was 8%. These data indicate that surgical revascularization can be performed safely with acceptable hospital mortality in high-risk patients with severe left ventricular dysfunction.

Long-term results of coronary artery bypass grafting in patients with left ventricular dysfunction

BACKGROUND

In this prospective study, we investigated the determinants of long-term outcome, symptoms, and left ventricular function after coronary artery bypass grafting in patients with a moderate to severely decreased left ventricular ejection fraction.

METHODS

Between 1997 and 1998, 75 consecutive patients with moderate to severe left ventricular dysfunction underwent coronary artery bypass grafting procedures. The operative mortality rate was 4.0%, and the 72 survivors were monitored for 8 years. The end points were mortality, symptomatic status (New York Heart Association [NYHA] functional class), and left ventricular function.

RESULTS

The total survival rate after 8 years was 89.3%. During follow-up, 8 patients died. Death was attributed to a cardiac cause in 5 patients and to a noncardiac cause in 3. There was no statistically significant difference between preoperative and late postoperative NYHA functional class, despite a statistically significant improvement that persisted for up to 4 years after CABG. The results of echocardiography showed a statistically significant improvement in the left ventricular ejection fraction (from 0.322 +/- 0.06 preoperatively to 0.463 +/- 0.02 at follow-up, p < 0.001). Multivariate analysis revealed that the left ventricular end-systolic volume index, the presence of angina pectoris, and absence of symptoms of congestive heart failure were preoperative indicators of freedom from heart failure after coronary operations (p < 0.05).

CONCLUSIONS

Coronary artery bypass grafting for patients with moderate-to-severe left ventricular dysfunction is associated with acceptable long-term results. The left ventricular end-systolic volume index is a simple noninvasive method to aid in the preoperative decision making in such patients.

Excellent Results of Contemporary Coronary Artery Bypass Grafting with Systematic Application of Modern Perioperative Strategies

BACKGROUND

The patient population referred for coronary artery bypass grafting (CABG) has become more challenging. The surgical population is aging and patients present with significant preoperative comorbidities. This worsening risk profile has led to the development of operative techniques (off-pump CABG) and perioperative measures (epi-aortic scanning, intensive insulin therapy) to preserve the quality of care following CABG. The aim of this study was to determine the outcome of contemporary CABG following the implementation of the above measures in our practice.

METHODS

We retrospectively analyzed prospectively collected data of 2725 patients undergoing CABG between 01/1998 and 12/2005 (mean age, 65 +/- 11 years; 843 [31%] female; mean ejection fraction, 45% +/- 14%). Outcome measures included hospital mortality, postoperative complications, and long-term survival and independent predictors of outcome. Subgroup analyses were performed for 2 study periods (1998-2002 versus 2003-2005) where the above measures were implemented and for patients undergoing conventional versus off-pump CABG.

RESULTS

When comparing the 2 study periods, we observed a substantial worsening of the risk profile with an increased EuroSCORE predicted mortality from 6.4% +/- 6.8% to 7.0% +/- 7.8% (P = .028). During the same period, operative mortality decreased from 2.4% to 0.7% (P < .001). This reduction in mortality was also observed in diabetic patients (3.1% versus 1.0%, P = .021) and those with low ejection fraction (4% versus 2.6%, P = not significant). Off-pump procedures were performed with an increasing frequency in high-risk patients in whom we obtained excellent results. Finally, we observed a reduction of postoperative complications including respiratory failure (P = .013), gastrointestinal complications (P = .017), and stroke (P = .094). Independent predictors of mortality included renal failure (OR = 5.7), peripheral vascular disease (OR = 2.9), intra-aortic balloon pump (OR = 4.8), reoperation (OR = 3.3), and hypertension (OR = 2.3).

CONCLUSION

Despite a worsening case mix, contemporary CABG can be performed with excellent results (operative mortality < 1%). Off-pump CABG performed in very high-risk patients obtains results similar to those of the general CABG population. Diabetes and ejection fraction were not independent predictors of early outcome. In our experience, these excellent outcomes were achieved by adopting an operative approach using modern perioperative management (epi-aortic scanning, intensive insulin therapy) and surgical techniques (off-pump CABG) based on individual patients.

Cardiac Transplantation: Any Role Left?

The authors analyze the question of whether heart transplantation still has a role in the current era of complex technologies. To achieve this objective, the authors first discuss the known benefits of different therapeutic modalities currently available for patients who have end-stage heart failure, including pharmacologic management, electrophysiologic therapies, high-risk surgical strategies, implantation of mechanical circulatory support device therapy, and heart transplantation. The authors then evaluate the current developments and future perspectives in the field that may influence the likelihood of heart transplantation to remain the therapeutic modality of choice for end-stage heart failure.

Nonpharmacologic therapy in heart failure: an overview

Heart failure therapy has seen significant changes over the past few decades. Therapies aimed at various pathophysiologic states have been and are currently used in the treatment of heart failure. Despite this, incidence and mortality continue to rise. Nonpharmacologic therapy plays a significant and life-saving role in certain subsets of patients. This review will discuss the current evidence and future direction of nonpharmacologic therapy as it pertains to surgical options, devices, and exercise.

Coronary Bypass Surgery for Patients with Chronic Poor Preoperative Left Ventricular Function (EF<30%): 5-year Follow-up

BACKGROUND

Optimal therapy for patients with coronary artery disease and chronic poor left ventricular function, given the absence of randomized trials, is unclear. Although coronary surgery has been performed in such patients for 25 years, it is perceived as high risk and unproven long-term benefit, especially if thallium scanning fails to demonstrate large areas of viability. We report the results of coronary surgery in these patients.

METHODS

Retrospective analysis by a standardized patient questionnaire, of 107 such consecutive patients offered coronary surgery.

RESULTS

Mean follow-up was 3.3 years (range, 0.5-5.5); average patient age was 64.4+/-1 years. Preoperative thallium scans were performed solely on 31 patients with none or mild angina, of which 10 (32%) demonstrated large areas of viable myocardium. Perioperative mortality was 1.9%. On multivariate analysis, factors predictive of increased perioperative death were recent myocardial infarction (p<0.001) and nonelective surgery (p<0.001). Kaplan-Meier 5-year survival and freedom from major adverse cardiac events were 72.3 and 82.3%, respectively. In 21 patients, with preoperative nil-to-mild angina and nil-to-small areas of myocardial viability, thallium scanning failed to predict a successful outcome.

CONCLUSION

Offering coronary surgery to these patients irrespective of thallium testing is safe and effective in the medium term. Early surgery is recommended.

Surgical therapies for heart failure

A variety of invasive procedures have been utilized to reduce the burden on the left ventricle in order to slow or reverse the progressive changes of structural remodeling. These include mitral valve repair, left ventricular assist devices, left ventricular chamber reduction surgery, endovascular patchplasty, dynamic cardiomyoplasty, and a variety of prosthetic implants designed to inhibit remodeling either by constraining chamber enlargement or reducing wall stress to inhibit further growth. Resynchronization therapy also may favorably affect remodeling. The potential of these procedures to slow the progression of heart failure needs to be confirmed in prospective studies.

[Prognosis scores to help revascularization for ischemic heart failure]

AIMS

Patients suffering from coronary heart disease with ventricular systolic dysfunction present a bad prognosis and should be potentially revascularized. Up to now, surgery appeared to be the most feasible revascularization technique for such patients. Aims of this study were to assess the influence of different treatments (surgery, angioplasty or exclusively medical treatment) on clinical outcome and to establish a prognostic score practitioners to select the most appropriate therapy adapted to their patient profiles.

METHOD

From 1995 to 2000, 492 patients were included in this cohort: 365 in the angioplasty group, 96 in the surgical group and 31 in the medical group. Kaplan Meier curves were made with a multivariate analysis to determine the significant predictive factors of mortality and major adverse cardiac events.

RESULTS

After a mean follow-up of 32 +/- 19 months, there was no statistical difference in mortality rate between the groups. However, the survival rate without MACE is higher in the surgical group, intermediate in the angioplasty group and lower in the medical group. Using the significant predictive factors of MACE in multivariate analysis, a prognostic score has been established in order to discriminate three categories of severity. For each category, angioplasty was compared with surgery in terms of the event-free-survival rate. For the two extreme categories (severe and non-severe), both treatments were equal. For the intermediate category, surgery obtained greater results.

CONCLUSION

This prognostic score could help physicians in choosing the appropriate revascularization technique to treat patients with severe ischemic heart failure.

Coronary revascularization in ischemic cardiomyopathy

This article first discusses coronary artery disease, including left-ventricular dysfunction, hibernating myocardium, the relationship between stunning, hibernation, and heart failure, and molecular mechanisms underlying myocardial hibernation. Left ventricular function and the prognosis and pathophysiology of left-ventricular dysfunction are then examined. Selection of patients for revascularization is discussed, to include which coronary patients should be investigated for myocardial viability, and other surgical considerations are outlined. The outcome following revascularization in the heart failure patient, the results of revascularization, and the time course of functional recovery after coronary artery bypass graft are also covered.

Coronary surgery with non-cardioplegic methods in patients with advanced left ventricular dysfunction: immediate and long term results

OBJECTIVE

To evaluate perioperative results and long term survival in patients with severe left ventricular (LV) dysfunction undergoing coronary artery bypass grafting (CABG) using non-cardioplegic methods.

METHODS

From April 1990 through December 1999, 4100 consecutive patients underwent isolated CABG using hypothermic ventricular fibrillation. Of these, 141 (3.4%) had severe LV dysfunction (ejection fraction < 30%). Mean age was 58.3 (9.6) years. 64 patients (45.4%) were in Canadian Cardiovascular Society class III or IV and 16 (11.3%) were subjected to urgent or emergent surgery. A previous myocardial infarction was recorded in 127 (90.1%). The majority (89.4%) had triple vessel and 26 (18.4%) had left main disease. The mean number of grafts per patient was 3.1. At least one internal thoracic artery was used in all patients and 21 (14.8%) had bilateral internal thoracic artery grafts (1.2 arterial grafts per patient).

RESULTS

Perioperative mortality was 2.8% (4 patients) and the incidence of acute myocardial infarction 2.8%. 50 (35.5%) patients required inotropes but only 16 (11.3%) required it for longer than 24 hours; 5 patients (3.5%) needed mechanical support. The incidence of renal failure was 3.5%. Mean duration of hospital stay was 9.6 (8.3) days. Follow up was 95% complete and extended for a mean of 57 (30) months. Late mortality was 11.5%. Actuarial survival rates at 1, 3, and 5 years were 96%, 91%, and 86%, respectively.

CONCLUSIONS

Non-cardioplegic techniques are safe and effective in preserving the myocardium during CABG in patients with coronary artery disease and poor LV function, with low operative mortality and morbidity, and encouraging medium to long term survival rates.

Precardiopulmonary bypass right ventricular function is associated with poor outcome after coronary artery bypass grafting in patients with severe left ventricular systolic dysfunction

Patients with severe left ventricular systolic dysfunction (LVSD) undergoing coronary artery bypass grafting (CABG) have an increased risk for morbidity and mortality. The purpose of this study was to assess the association of pre-CABG right ventricular (RV) function with outcome for patients with severe LVSD. We performed a retrospective evaluation of 41 patients with severe LVSD (left ventricular ejection fraction [LVEF] < or =25%) scheduled for nonemergent CABG. Data were obtained from review of medical records, transesophageal echocardiography tapes, and phone interview. The pre- and post-cardiopulmonary bypass (CPB) LVEF and the RV fractional area of contraction (RVFAC) were calculated by using intraoperative transesophageal echocardiography. Group 1 patients had an RVFAC < or =35% (n = 7), whereas Group 2 patients had RVFAC >35% (n = 34). The durations of mechanical ventilation and of intensive care unit and hospital stays are presented as the median. Pre-CABG LVEF was similar between Groups 1 and 2 (15.8% +/- 3.3% versus 17.8% +/- 3.9%). Compared with Group 2, Group 1 patients required greater duration of mechanical ventilation (12 days versus 1 day; P < 0.01), longer intensive care unit (14 versus 2 days; P < 0.01) and hospital (14 versus 7 days; P = 0.02) stays, had a more frequent incidence and severity of LV diastolic dysfunction, and had a smaller change in LVEF immediately after CPB (4.1% +/- 8.3% versus 12.5% +/- 9.2%; P = 0.03). All Group 1 patients died of cardiac causes within 2 yr of surgery; five died during the same hospital admission. Three Group 2 patients died: one of colon cancer at 18 mo after CABG and two of cardiac causes 24 and 48 mo after surgery. A fourth patient was awaiting cardiac transplantation 4 yr after surgery. The remaining Group 2 patients were New York Heart Association Classification I or II. For patients with severe LVSD undergoing CABG, pre-CPB RV dysfunction was associated with poor outcome. Patients with RVFAC >35% had a relatively uneventful perioperative course and good long-term survival, whereas patients with RVFAC < or =35% had a poor early and late outcome. Assessment of RV function is useful to further assess the risk of CABG.

IMPLICATIONS

Right ventricular function before cardiopulmonary bypass is associated with poor outcome after coronary artery surgery in patients with poor left ventricular function.

Coronary artery bypass grafting in patients with poor left ventricular function

Coronary artery bypass grafting (CABG) in patients with poor left ventricular function remains a surgical challenge and is still controversial. The purposes of this study were to evaluate the effectiveness of CABG in such patients when performed without case selection on the basis of preoperative viability tests and to determine the predictors of postperative outcome. The preoperative, perioperative, and postoperative early and mid-term follow-up data of 273 patients with < or = 30% left ventricular ejection fraction (LVEF) who underwent isolated CABG between January 1995 and November 2000 were evaluated. Preoperative echocardiography and cardiac catheterization, and postoperative control echocardiography were performed in all patients. Follow-up was achieved via monthly periodical examinations in the first 6 months, and thereafter by either regular visits or phone contact. Preoperatively, 242 (88.65%) patients were in NYHA class III or IV, and the mean LVEF was 26.51 +/- 3.64%. The overall hospital mortality total was 14 (5.13%) patients. There were 44 (16.12%) late mortalities. Postoperative morbidities were observed in 74 (27.1%) patients. Two-hundred and two (93.95%) of the surviving 215 (78.75%) patients were in NYHA class I or II at 49.55 +/- 14.84 months of follow-up. Postoperative follow-up echocardiographic examinations revealed a mean LVEF of 39.66% +/- 5.43%. The improvements in functional capacity and LVEF were significant. Advanced age, diabetes, hypertension, cross-clamp time >60 min, bypass time>120 min, and severity of functional class (class III-IV of NYHA) were found to be the determinants of mortality. However, multivariate analyses revealed only older age and class III-IV of NYHA and CCS were predictors of mortality. The low mortality and morbidity rates as well as satisfactory postoperative improvements in functional capacity and LVEF measurements support the use of CABG without the need for any viability assessment in patients with left ventricular dysfunction.

Surgical management of heart failure: an overview

Cardiac transplantation remains the gold standard of surgical therapies for advanced and end-stage heart failure. However, this very limited option trades one disease for another and can benefit only a small minority of patients. Heart failure is currently considered secondary to a structural increase in ventricular chamber volume or remodeling. Surgical therapies formerly contraindicated for the failing heart, as well as new therapies, can successfully affect ventricular remodeling and improve cardiac function. Surgical revascularization for patients with ejection fractions <20% is becoming common. Mitral valve repair is being explored, with surprisingly low operative mortality and encouraging intermediate results. Direct surgical approaches to restoring normal geometry and size to failing hearts, such as left ventricular reduction (Batista procedure), endoventricular patch plasty (Dor procedure), cardiomyoplasty, and prosthetic external constraints are under clinical investigation. Developments in mechanical assist therapy and a new generation of implantable intracorporeal assist devices are also discussed.

Clinical assessment in ischaemic cardiomyopathy

Despite the trend of decreasing death rates attributable to ischaemic heart disease and stroke, the prevalence of heart failure and the resultant death rates in the United States have almost tripled between 1974 and 1994 [1]. Coronary artery disease is the commonest cause of heart failure in developed countries, accounting for up to 60% of cases. Advances in medical therapy, particularly the use of angiotensin-converting enzyme inhibitors and beta-blockers, have served to reduce morbidity and mortality in patients with left ventricular (LV) dysfunction due to coronary artery disease [2-5]. However, these improvements have been modest, and despite these therapies, patients with severe ischaemic cardiomyopathy continue to have a high mortality when treated medically. It is increasingly clear that the impaired LV function in these patients is not always an irreversible process. Traditionally, these observations have been made following demonstrable improvements in systolic function after coronary revascularization procedures. Diagnostic testing to evaluate the presence and extent of viable myocardium has therefore become an important component of the clinical assessment of patients with chronic coronary artery disease and LV dysfunction.

Coronary artery bypass grafting in patients with severe left ventricular dysfunction: a prospective randomized study on the timing of perioperative intraaortic balloon pump support

In this prospective trial the results of preoperative and intraoperative IABP in coronary artery bypass graft (CABG) patients with low left ventricular ejection fraction (LVEF) were compared. Sixty CABG patients with preoperative LVEF < or = 0.30 were enrolled: in group A patients (n=30) IABP was started within 2 hours preoperatively; in group B (n=30) it was instituted intraoperatively before weaning from cardiopulmonary bypass. Cardiac performance was assessed through Swan-Ganz catheter monitoring and daily echocardiography. Hospital survival, length of IABP support, intubation, ICU and hospital stay, need for postoperative inotropic drugs and incidence of myocardial infarction were compared between the two groups. Survival in group A patients proved significantly higher (P=0.047). Cardiac performance after myocardial revascularization improved in both groups with significantly better outcomes in group A patients (P<0.001). Doses of inotropic drugs (dobutamine, enoximone) were lower in group A (P=0.001; P=0.004) and duration shorter (P<0.001; P<0.001). No major IABP-related complication was observed.

Myocardial revascularization in patients with severe ischemic left ventricular dysfunction. Long term follow-up in 141 patients

OBJECTIVES

The present study evaluates our experience with coronary bypass grafting in patients with EF < or =25%. Myocardial revascularization in this setting remains controversial because of concerns over operative mortality and morbidity and lack of functional and survival benefit.

MATERIALS AND METHODS

One hundred and forty-one patients with coronary artery disease and left ventricular ejection fraction < or =25% underwent coronary artery bypass graft between January 1988 and December 1998. Mean age at operation was 63.3 years and 81.4% were male. The major indication for surgery was angina (114 patients, 80.8%). Ejection fraction (EF), left ventricular end diastolic pressure (LVEDP) and cardiac index (CI) were used to assess left ventricular function. The number of graft was 2.7+/-1.6/patient. Internal mammary artery was used in 119 patients (84.3%). Intra aortic balloon pump was placed preoperatively in 25 patients (17.7%). Five operative risk factors were associated with a higher mortality: emergency, female sex, LVEDP, CI and NYHA class IV.

RESULTS

The operative mortality was 7% (10 patients). Left ventricular ejection fraction (assessed post operatively in 83 patients) improved from 22.2% preoperatively to 33.5% post operatively (P<0.001), mean end diastolic volume index fell from 98 to 83 ml/m(2) following surgery. Survival at 2, 5 and 7 years was respectively 84+/-3%, 70+/-4% and 50+/-5%. Two variables were associated with increased long term survival: congestive heart failure (NYHA class lower than IV (P=0.035) and cardiomegaly (P=0.04)

CONCLUSION

In patients with left ventricular dysfunction, myocardial revascularization can be performed relatively safely with good medium term survival and improvement in quality of life and in left ventricular function. Coronary artery bypass graft may be offered to patients with impaired ventricular function, but careful patient selection and management when considering these patients for operation should assess potentially reversible dysfunction.

Coronary artery surgery for ischemic heart failure: risks, benefits, and the importance of assessment of myocardial viability

Heart failure and left ventricular dysfunction are common and are most often caused by myocardial ischemia/infarction secondary to occlusive coronary artery disease. Although recent refinements in medical therapy have resulted in improved survival, morbidity and mortality remain high in patients with advanced heart failure. Heart transplantation remains an option for selected patients, and implantable left ventricular assist devices may soon provide another treatment strategy for such patients. However, patients with established postischemic heart failure, significant myocardial viability, and coronary artery anatomy amenable to surgical revascularization can derive significant functional and survival benefit after coronary artery surgery, albeit with an increased perioperative risk. We discuss the role of coronary artery surgery in ischemic heart failure and review the evidence for such an approach.

Heart transplantation indicated only in the most severely ill patient: perspectives from the German heart transplant experience

The COCPIT study, performed in a complete national cohort of adult patients consecutively listed for cardiac transplantation in Germany in 1997, found a beneficial effect only in the group that was at high risk of dying from heart failure without transplantation. If these results can be reproduced in other countries, the discussion on the respective roles of pharmacological and organ-saving surgical therapies for advanced heart failure, medical urgency and waiting time as heart transplantation allocation criteria, and the feasibility of a randomized clinical trial testing the survival benefit of transplantation must be reopened.

Results of revascularization in patients with severe left ventricular dysfunction

OBJECTIVE

In patients with coronary disease and poor left ventricular function, bypass grafting remains a surgical challenge. This study evaluates experience in 125 consecutive patients with ejection fraction less than 20% (study group).

METHODS

Preoperative viability studies were not used for patient selection. Clinical data were prospectively collected. The average age of the study subjects was 59 +/- 9 years, and 112 (90%) were male. Most patients (108 [86%]) were in symptom class III or IV. Main indications for surgery included angina in 62 (50%), heart failure and angina in 36 (29%), heart failure in 9 (7%), ventricular arrhythmia in 2 (2%), and critical anatomy in 16 (13%). Significant mitral regurgitation was present in 48 (38%), and distal vessels were poorly visualized in 67 (54%). At surgery, temperature mapping guided an integrated approach to cold cardioplegia. Results in this group were compared with those obtained in case-matched control subjects receiving cardioplegia without temperature mapping (matched for age, sex, functional class, and urgency of operation).

RESULTS

Hospital morbidity (intra-aortic balloon pump support) and mortality rates were significantly lower in the study group versus those of control subjects (15% vs 30%, P =. 004; and 4% vs 11%, P =.03, respectively). In study patients the 5-year actuarial survival was 72%. Among survivors, both anginal class and heart failure class improved significantly. By means of multivariate analysis, survival was adversely affected by older age, class IV symptoms, and poorly visualized distal vessels.

CONCLUSIONS

These results support the use of coronary artery bypass grafting in patients with severe left ventricular dysfunction without case selection on the basis of viability studies or visibility of distal vessels. Low hospital morbidity and mortality rates have been achieved when temperature mapping guides cardioplegia. Symptoms are improved in most patients, and long-term survival is encouraging.

Left ventricular volume reduction and reconstruction in ischemic cardiomyopathy

BACKGROUND

Ischemic cardiomyopathy can be the result of large or small myocardial infarctions or due to myocardial hibernation. Patients with an end-systolic volume index >100 mL¿m2 do not benefit from revascularization alone and require an operation that reduces ventricular volume. Various approaches to reduce ventricular volume have been described. We applied several of these techniques in patients with end-stage ischemic cardiomyopathy.

METHODS

Forty eight patients with end-stage ischemic cardiomyopathy (Class III-IV) underwent left ventricular volume reduction operations with coronary revascularization and mitral valve repair or Alfieri valvoplasty. Fourteen patients underwent interpapillary resections, 22 anterior resections, 4 posterior resections, 2 anterior and posterior resections, and 6 patients reduction of left ventricular volume with endocavitary patches.

RESULTS

All the techniques used improved left ventricular function. Analysis of mortality revealed that extensive resections (interpapillary, anterior, and posterior resection) had a 43% mortality. However, a limited resection or a ventricular reconstruction with an endocavitary patch had only a 12.5% mortality. When we changed our approach to a more conservative one, mortality was reduced from 26% the first 12 months to 13% in the last 15 months of the study.

CONCLUSIONS

Ischemic cardiomyopathy has a poor prognosis if the end-systolic volume index exceeds 100 mL/m2. Various procedures exist to reduce left ventricular volume. Extensive ventricular resections improve ventricular function, but have a high mortality. This led us to use other methods of ventricular volume reduction such as more conservative resections combined with left ventricular reconstructions or ventricular volume reduction with endocavitary patches. Mortality was reduced significantly by this approach. The patients that survived have remained Class I-II in a follow-up that extends up to 30 months. Surgical therapy of Class III-IV ischemic cardiomyopathy is feasible, but aggressive ventricular resections have a high mortality. We advocate a more reconstructive approach with limited or no ventricular resection.

Myocardial viability during dobutamine echocardiography predicts survival in patients with coronary artery disease and severe left ventricular systolic dysfunction

OBJECTIVES

The purpose of this study was to assess whether the presence or absence of myocardial viability during dobutamine echocardiography (DE) predicts survival in patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction.

BACKGROUND

In patients with CAD, the presence of myocardial viability during DE identifies viable myocardium and predicts recovery of LV systolic function after revascularization. However, there is little data on the relation between myocardial viability and clinical outcome in patients with CAD and severe LV dysfunction.

METHODS

We studied 318 patients with CAD and a LV ejection fraction (EF) < or =35% who underwent DE and were followed for 18+/-10 months. Patients were classified into four groups. Group I (n=85) consisted of patients who had evidence of myocardial viability and subsequently underwent revascularization. Group II (n=119) consisted of patients with myocardial viability who did not undergo revascularization. Group III (n=30) consisted of patients who did not have myocardial viability and underwent revascularization. Finally, group IV (n=84) patients lacked myocardial viability and did not undergo revascularization.

RESULTS

The four groups had similar baseline characteristics and rest LVEF. During follow-up there were 51 deaths (16%). The mortality rate was 6% in group I, 20% in group II, 17% in group III and 20% in group TV (p=0.01, group I vs. other groups).

CONCLUSIONS

In patients with CAD and severe LV dysfunction who demonstrated myocardial viability during DE, revascularization improved survival compared with medical therapy.

Efficacy of coronary artery bypass grafting in patients with a dilated left ventricle due to myocardial infarction

This study was designed to clarify the efficacy of coronary artery bypass grafting (CABG) on left ventricular (LV) function in 16 patients with a dilated LV due to myocardial infarction (LV end-systolic volume index: LVESVI >60 ml/m2). All had attained complete revascularization. To estimate the LV wall motion quantitatively using echocardiography, a wall motion score (WMS) was used (LV was divided into 17 segments with a four-point scale: akinesis=3, severe hypokinesis=2, hypokinesis=1, normal=0 and then summed). Exercise stress tests were performed after surgery, revealing that anginal symptoms had vanished in all the patients. In 5 patients with a preoperative end-systolic volume index (ESVI) >100 ml/m2, the ejection fraction (EF) did not change, and both were under 30% (before to after: 26+/-4 to 26+/-4%). Neither the ESVI (148+/-50 to 133+/-39 ml/m2) nor the end-diastolic volume index (end-diastolic volume index (EDVI): 198+/-62 to 180+/-37 ml/m2) changed; the WMS did not change (33+/-2 to 33+/-3). During exercise, in spite of the increase in heart rate (HR) (at rest, 81+/-20; HR during exercise, 111+/-21 beats/min, p<0.005) and LV end-diastolic pressure (EDP) (22+/-9; 35+/-13 mmHg, p<0.02), both cardiac index (CI) (2.4+/-0.3; 2.6+/-0.4 L/min x m2) and minute work (MW: 4.0+/-1.1; 4.1+/-0.4 kg x M/min) did not increase. In 11 patients with a preoperative ESVI <100 ml/m2, EF was extremely increased in 5 patients (more than 10%, 35+/-4 to 60+/-6%, p<0.005=improved subgroup) in whom the EDVI (130+/-16 to 120+/-13 ml/m2) did not change whereas the ESVI (82+/-14 to 48+/-7 ml/m2) was reduced. However, in the 6 remaining patients (ie nonimproved subgroup), neither ESVI (78+/-8 to 74+/-12 ml/m2), EDVI (115+/-10 to 115+/-20 ml/m2) nor EF (31+/-7 to 35+/-3%) changed. During exercise, HR (at rest, 88+/-13; during exercise, 108+/-11 beats/min, p<0.005), LVEDP (20+/-6; 29+/-7 mmHg, p<0.01), CI (2.5+/-0.6; 3.3+/-0.5 L/min x m2, p<0.05), MW (4.6+/-1.0; 6.5+/-1.5 kg x M/min, p<0.05) increased. The WMS in the nonimproved subgroup did not change (29+/-6 to 27+/-2), but in the improved subgroup it reduced after surgery (27+/-3 to 19+/-4, p<0.01). These data suggested that CABG in patients with a dilated LV was effective against anginal symptoms, but was restricted to left ventricular function. It may be possible to estimate postoperative LV function, including exercise tolerance, from the preoperative LVESVI.

Ventricular remodelling and revascularization in severe left ventricular dysfunction

OBJECTIVE

To evaluate the role of surgical revascularization in the presence of severe, global impairment of left ventricular function without discrete aneurysm formation or mitral regurgitation. The high mortality and morbidity associated with this group, together with the limited benefits tend to prompt referral for cardiac transplantation.

METHODS

Fifty-three patients initially referred for transplantation, in addition to coronary revascularization, underwent mitral annuloplasty (group A = 23), free wall remodelling by endoaneurysmorrhaphy (group B = 17) or mitral annuloplasty and free wall reconstruction (group C = 13). The mean ages were 59, 56 and 57 years for groups A, B and C, respectively. Detailed assessment of pre- and post-operative physical and psychological status were carried out.

RESULTS

Follow-up was for a mean period of 22-26 months. All patients reported substantial improvement in quality of life, both physical and psychological parameters and in NYHA functional class status. Objective evidence of improvement in ejection fraction was seen in all three groups but especially in group A. There were five early deaths, four were due to inadequate revascularization due to the poor quality of target vessels. There were three late deaths and one patient that required transplantation.

CONCLUSION

We conclude that patients with severe left ventricular dysfunction can be candidates for surgical revascularization and optimization of ventricular geometry with acceptable mortality. The importance of achieving complete revascularization is emphasized in this series.

Left ventricular volume predicts postoperative course in patients with ischemic cardiomyopathy

BACKGROUND

The left ventricular end-systolic volume index (LVESVI) helps to predict postoperative left ventricular function in patients with ischemic cardiomyopathy.

METHODS

We retrospectively assessed the ability of preoperative variables to predict death and the development of postoperative congestive heart failure in 41 patients with a preoperative ejection fraction of less than 0.30.

RESULTS

A preoperative LVESVI of greater than 100 mL/m2 was identified as an independent predictor of death by Cox's proportional hazards model. Diabetes and a preoperative LVESVI of greater than 100 mL/m2 were independent predictive risk factors for the development of postoperative congestive heart failure. Postoperative congestive heart failure developed in 2 of the 23 patients (8.7%) who had a preoperative LVESVI of less than 100 mL/m2 and in 10 of the 16 patients (62.5%) who had a preoperative LVESVI of greater than 100 mL/m2. The actuarial survival rate during follow-up in patients who had a preoperative LVESVI of less than 100 mL/m2 was significantly greater than that in patients who had a preoperative LVESVI of greater than 100 mL/m2. The actuarial rate of freedom from congestive heart failure during the follow-up period also was greater in patients who had a preoperative LVESVI of less than 100 mL/m2.

CONCLUSIONS

Our results suggest that the preoperative LVESVI predicts the development of postoperative congestive heart failure and the actuarial survival rate in patients with ischemic cardiomyopathy.

Baseline characteristics of patients in the coronary artery bypass graft (CABG) Patch Trial

BACKGROUND

Patients with left ventricular dysfunction who undergo coronary artery bypass graft (CABG) surgery frequently have late sudden cardiac death. The CABG Patch Trial is a prospective, randomized, multicenter clinical trial that randomized patients at high risk at the completion of CABG surgery to implantation of an epicardial implantable cardioverter defibrillator (ICD) or to no antiarrhythmic treatment. The trial was designed to determine whether prophylactic implantation of an ICD at the time of CABG surgery would result in a lower total mortality in long-term follow-up.

METHODS

Patients undergoing CABG surgery were eligible for the trial if they were younger than 80 years, had a left ventricular ejection fraction less than 0.36, and had an abnormal signal averaged electrocardiogram. Patients with a history of sustained ventricular tachycardia or ventricular fibrillation were excluded from the trial. All patients were scheduled to undergo follow-up at 3-month intervals until 42 months after surgery.

RESULTS

Randomization of patients in the trial ended in February 1996. During the recruitment period 71,855 patients were screened, 1,422 were eligible, 1,055 were enrolled (signed consent forms), and 900 patients (76% of eligible patients) were randomized. The mean age of the 446 patients in the ICD group was 64 years versus 63 years for the 454 patients in the control group. A total of 87% of the participants in the ICD group were men versus 82% in the control group (p = NS). Most of the patients had a history of hypertension (55%), smoking (78%), and hypercholesterolemia (54%). Half of the patients had clinical heart failure, and the mean ejection fraction for both patient groups was 0.27 +/- 0.06. No difference was seen in the history of myocardial infarction (83%), congestive heart failure (50%), or atrial (11%) or ventricular (17%) arrhythmias between the two groups. Major clinical characteristics (age, sex, number of previous infarctions, incidence of heart failure, and mean left ventricular ejection fraction) were almost identical to those found in another ICD primary prevention trial, the Multicenter Automatic Defibrillator Implantation Trial (MADIT).

CONCLUSIONS

A high risk sample of patients was enrolled in The CABG Patch Trial, as shown by examination of their baseline characteristics.

Predictors of early and overall outcome in coronary artery bypass without cardiopulmonary bypass

OBJECTIVE

Cardiopulmonary bypass in coronary artery bypass graft operations may adversely affect the outcome especially in high-risk patients. The purpose of this study is to evaluate results of coronary artery bypass performed without cardiopulmonary bypass, in a relatively high-risk cohort, and to identify predictors of unfavorable outcome.

METHOD

Three hundred and thirteen (313) patients, 246 (79%) of whom had high-risk conditions, who have a coronary anatomy suitable for coronary artery bypass surgery without cardiopulmonary bypass, underwent this procedure between December 1991 and July 1995. Mean number of grafts/patient was 1.8 (1-5), and only 71 patients (23%) received a graft to the circumflex coronary system.

RESULTS

Early unfavorable outcome events included operative mortality (12 patients, 3.8%), nonfatal perioperative myocardial infarction (eight patients, 2.6%), emergency reoperation (three patients, 0.9%), sternal infection (five patients, 1.6%), and nonfatal stroke (two patients, 0.6%). Multivariate analysis revealed angina pectoris class IV (odds ratio 5.4) and age > or = 70 years (odds ratio 5.0) as independent predictors of early mortality. Preoperative risk factors such as repeat coronary artery bypass grafting (50 patients, 16%), ejection fraction < or = 0.35 (85 patients, 27%), acute myocardial infarction (86 patients, 28%), cardiogenic shock (ten patients, 3.2%), chronic renal failure (25 patients, 8%), chronic obstructive pulmonary disease (20 patients, 6%), and peripheral vascular disease (51 patients, 16%) did not increase early mortality. During 33 months of follow-up (range 1-57 months), there were 42 deaths, at least 16 cardiac-related (one and four years actuarial survival of 90% and 76% respectively), and 39 patients (12.5%) in whom angina returned. Calcified aorta (odds ratio 2.6) and old myocardial infarction (odds ratio 1.8) were independent predictors of overall unfavorable events.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass can be performed with relatively low operative mortality in certain high-risk subgroups of patients; however, an increased risk of graft occlusion is a potential disadvantage. This procedure should therefore be considered only for patients with suitable coronary anatomy, in whom cardiopulmonary bypass poses a high risk. Although the risk of stroke is relatively low, the procedure is still hazardous for patients aged 70 years and over.

Primary coronary artery bypass grafting without cardiopulmonary bypass in impaired left ventricular function

BACKGROUND

Conventional coronary artery bypass grafting using cardiopulmonary bypass carries relatively high mortality and morbidity for patients with left ventricular dysfunction.

METHODS

Seventy-five patients with ejection fraction less than or equal to 0.35 underwent primary coronary artery bypass grafting without cardiopulmonary bypass between December 1991 and December 1994. Thirty-two patients (43%) had congestive heart failure, 11 (15%) were referred for operation within the first 24 hours of evolving myocardial infarction, and 21 (28%) up to 1 week after acute myocardial infarction. Eighteen patients (24%), 6 of whom were in cardiogenic shock, underwent emergency operations.

RESULTS

Mean number of grafts/patient was 1.9 (range, 1 to 4), and internal mammary artery was used in 66 patients (85%). Only 17 patients (23%) received a graft to a circumflex marginal artery. Two patients (2.7%) died perioperatively, and 1 (1.3%) sustained stroke. At mean follow-up of 28 months, 13 patients had died, and angina had returned in 7 (10.5%). One- and four-year actuarial survival was 96% and 73%, respectively.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass is a viable alternative to conventional coronary artery bypass grafting particularly for patients with extreme left ventricular dysfunction or those with coexisting risk factors, such as acute myocardial infarction and cardiogenic shock.

Coronary artery bypass grafting in patients with chronic congestive heart failure: a 10-year experience with 203 patients

From 1983 to 1992, 203 patients with chronic congestive heart failure and no angina underwent primary coronary artery bypass. This represented 3% of patients undergoing coronary artery bypass grafting. Ninety-two percent of the patients were in New York Heart Association (NYHA) functional class III or IV prior to undergoing coronary artery bypass grafting. Thallium perfusion imaging was performed in 21% of the patients, with a reversible defect present in 88%. An internal mammary artery graft was used in 70% of the patients. The hospital mortality was 6.0% and the actuarial survival at 5 years was 59%. An improvement in NYHA functional class occurred in 75% of the surviving patients with a mean improvement of 1.6 +/- 0.6 functional classes. Univariate analysis identified risk factors for hospital death as emergency operation, recent myocardial infarction (< 30 days), and the need for an intra-aortic balloon pump. A trend emerged for nonuse of an internal mammary artery to predict hospital death. A positive thallium perfusion scan was not a predictor of early or late survival, nor did it influence NYHA functional class. The use of the internal mammary artery significantly enhanced late survival (p = 0.01), however, did not affect the functional class of survivors. We conclude that coronary artery bypass grafting is effective in ameliorating symptoms of chronic congestive heart failure in patients suffering from chronic ischemic cardiomyopathy and can be performed with acceptable early and late mortality.

Predictors of long-term survival in patients with malignant ventricular arrhythmias

The study consisted of 369 patients (age 62 +/- 13 years) who presented to our institution from April 1984 to April 1994 for malignant ventricular arrhythmias presenting as sustained ventricular tachycardia (VT) in 57% of patients, ventricular fibrillation in 25% of patients, and syncope due to VT in 17% of patients. Coronary artery disease was present in 74% of patients, cardiomyopathy in 19% of patients, and no evident heart disease in 7% of patients. Two hundred twenty-one patients were given drug, therapy, 47 patients underwent arrhythmia surgery, and 75 patients had an implantable cardioverter-defibrillator (ICD). During a mean follow-up of 30 months (range 1 to 101), 66 patients (18%) died from a cardiac death of which 26 (39%) were sudden. Cox regression analysis was conducted utilizing a total of 19 variables (clinical and therapeutic) in the entire population and separately in patients with coronary artery disease and cardiomyopathy. The most significant variables (multivariate analysis) of survival from cardiac mortality in the entire population were: congestive heart failure (CHF) class (p = 0.0003), ejection fraction (p = 0.02), and the use of drug therapy (p = 0.03); in patients with coronary artery disease, CHF class (p = 0.0001) and ejection fraction (p = 0.0006); and in patients with cardiomyopathy, CHF class (p = 0.009) and sustained VT on Holter monitoring (p = 0.007). Kaplan-Meier survival rates from cardiac death were: significantly lower (p = 0.005) in patients with CHF class III and IV compared with CHF class I and II (25% vs 58%, p = 0.005) with drug therapy; marginally significant (47% vs 88%, p = 0.06) from 20 to 40 months in patients with an ICD; and nonsignificant in patients who underwent arrhythmia surgery (63% vs 71%). Patients with an ICD had a better expected survival (82%) than patients who had arrhythmia surgery (69%) and drug therapy (65%). Thus, in patients with malignant ventricular arrhythmias, CHF class was the most significant independent predictor of survival from cardiac mortality over all disease substrates, and therapy influenced survival depending on the CHF class. Patients in CHF class III and IV who underwent arrhythmia surgery or had an ICD had a better expected survival than those taking drug therapy, and the negative impact of antiarrhythmic therapy was most prominent in patients with CHF class III and IV.

Minimal operative mortality in patients undergoing coronary artery bypass with significant left ventricular dysfunction by maximization of metabolic and mechanical support

Between January 1, 1992, and January 23, 1996, 111 consecutive patients with severe left ventricular dysfunction underwent isolated coronary artery bypass grafting. The ejection fraction in these patients ranged from 10% to 34% (mean 27.9% +/- 5.4%); in 18 patients the value was less than 20%. The high operative mortality rate (7.6% in Society of Thoracic Surgeons database) in this group of patients at high risk was targeted for reduction by provision of, in addition to the usual inotropic support, progressively more intensive metabolic and mechanical support. The metabolic support consisted of triiodothyronine; glucose, insulin, and potassium; aspartate/glutamate in the cardioplegic solution; and warm-cold-warm/antegrade-retrograde-antegrade cardioplegia. Mechanical support included liberal use of the intraaortic balloon pump, use of a new occlusive retrograde cardioplegia catheter, ultrafiltration to remove myocardial depressant factors, and, finally, delayed sternal closure. The operative mortality rate was 1.8% (2/111). Complications included reoperation because of bleeding (3.6%, 4/111), mediastinitis (1.8%, 2/111), and stroke (0.9%, 1/111) and there were no occurrences of new postoperative acute renal failure (0.0%, 0/111). The intensive care unit stay was 2.2 +/- 0.9 days with a length of stay in the hospital of 13.7 +/- 22.1 days. These techniques done before operation, intraoperatively, and postoperatively optimize the milieu of the depressed left ventricle by maximizing perioperative high-energy phosphate bonds; increasing the effectiveness of inotropic agents; unloading the left ventricle by chemical, metabolic, and mechanical support; and removing known myocardial depressant factors, which reduced the operative mortality rate to 1.8% compared with 7.6% as reported in the Society of Thoracic Surgeons' database.

Inappropriate use of bivariable analysis to screen risk factors for use in multivariable analysis

The use of bivariable selection (BVS) for selecting variables to be used in multivariable analysis is inappropriate despite its common usage in medical sciences. In BVS, if the statistical p value of a risk factor in bivariable analysis is greater than an arbitrary value (often p = 0.05), then this factor will not be allowed to compete for inclusion in multivariable analysis. This type of variable selection is inappropriate because the BVS method wrongly rejects potentially important variables when the relationship between an outcome and a risk factor is confounded by any confounder and when this confounder is not properly controlled. This article uses both hypothetical and actual data to show how a nonsignificant risk factor in bivariable analysis may actually be a significant risk factor in multivariable analysis if confounding is properly controlled. Furthermore, problems resulting from the automated forward and stepwise modeling with or without the presence of confounding are also addressed. To avoid these improper procedures and deficiencies, alternatives in performing multivariable analysis, including advantages and disadvantages of the BVS method and automated stepwise modeling, are reviewed and discussed.

Coronary artery bypass grafting in patients with an ejection fraction of twenty percent or less

Over a 7-year period, 5.8% (n = 210) of patients who underwent coronary artery bypass grafting at our institution had severely impaired global left ventricular function with an ejection fraction of 20% or less. Mean age at operation was 66 years (+/- 0.7; standard error), and 76% of patients were male. Primary indications for operation were unstable angina (73 patients, 35%), return of symptoms with previous bypass grafting (41 patients, 20%), congestive heart failure with reversible ischemia (55 patients, 26%), and recurrent ventricular arrhythmias (41 patients, 20%). Overall, actuarial survival (n = 210) was 82%, 79%, and 73% at 1, 2, and 5 years. Risk of death was highest early after the operation, and then declined rapidly to a constant level. Patients who did not receive retrograde coronary sinus cardioplegia (p = 0.05), older patients (p = 0.004), and those with preoperative ventricular arrhythmias (p = 0.003) or renal failure (p < 0.0001) had an increased risk of death early after operation. Patients with congestive symptoms and those requiring extensive or redo bypass grafting (p = 0.02) were found to be at an increased risk of death throughout the follow-up period. When the number of distal anastomoses performed increased, survival was found to decrease (p < 0.003), and to a greater extent in women than in men (p = 0.02). Of the four primary indications for operation, unstable angina yielded the highest risk-adjusted survival. Successful results after surgical revascularization in patients with severe impairment of ventricular function can be achieved by careful patient selection and management.

Results of revascularization in patients with severe left ventricular dysfunction

BACKGROUND

In patients with coronary artery disease and poor ventricular function (ejection fraction, < 20%), bypass grafting remains a surgical challenge. This study evaluates experience with isolated revascularization in such patients.

METHODS AND RESULTS

In 79 consecutive patients (69 men, 10 women; average age, 59 +/- 9 years), preoperative ejection fraction was 18 +/- 5%. Indications for surgery were congestive heart failure (CHF) in 5 of 79 patients (6%), CHF and angina in 19 (24%), angina in 41 (52%), ventricular arrhythmias (VAs) in 8 (10%), and critical anatomy in 6 (8%). Some patients had prior VAs (23 of 79; 29%) or mitral regurgitation (18; 23%) and required emergent surgery (25; 32%). At surgery, temperature mapping ensured adequate distribution of antegrade cold cardioplegia, with 3.6 +/- 0.7 grafts per patient, including left internal mammary artery graft in 60 of 79 (76%) and endarterectomy in 14 (18%). Hospital mortality was 3.8%. Perioperative support included intra-aortic balloon pump in 18 of 79 (23%) and drugs for VAs in 28 (35%). Morbidity included myocardial infarction in 2 of 79 (2.5%) and stroke in 2 (2.5%). During follow-up, there were 19 late deaths. Actuarial survival was 94%, 82%, and 68% at 1, 2, and 5 years, respectively, and was similar in patients with severe angina, CHF, mitral regurgitation, or VAs. Freedom from sudden death was 100%, 98%, and 91% at 1, 2, and 5 years, respectively. Among survivors, angina improved in 84% and heart failure improved in 26%.

CONCLUSIONS

These data support bypass graft surgery in patients with severe LV dysfunction. With careful cardioplegic techniques, hospital mortality was low (3.8%). Long-term survival is encouraging, with good relief of symptoms in most patients. Perioperative VAs are frequent but respond to medical treatment, with only 23% of patients discharged on antiarrhythmic drugs. Five-year freedom from sudden death is 91%, with only 3 late sudden deaths in this series.

Predicting survival after coronary revascularization for ischemic cardiomyopathy

BACKGROUND

The success of coronary revascularization for ischemic cardiomyopathy (left ventricular ejection fraction of 0.25 or less) has been unpredictable. We and others have demonstrated that the hospital operative mortality rate for these operations has been surprisingly low, particularly if evidence of ischemia is present. We subsequently liberalized our selection criteria based on our hypothesis that coronary artery bypass grafting is safe in this subset of patients regardless of the status of their distal coronary vasculature.

METHODS

To examine this hypothesis, we studied retrospectively our patients undergoing coronary artery bypass grafting from 1983 to 1993. Ninety-six patients with ejection fractions of 0.25 or lower underwent this operation, with 88 hospital survivors (mortality 8%). All of the patients had clinical symptoms of heart failure. The male to female ratio was 4.6:1. The average age was 63.1 +/- 0.9 years (mean +/- standard error of the mean). Patients were excluded if they had valvular heart disease other than mild to moderate mitral regurgitation, required resection of a ventricular aneurysm, or required an emergency operation for acute coronary occlusion. Possible predictors of death were examined retrospectively. The catheterization films were reviewed retrospectively by a cardiovascular surgeon who was blinded to patient outcome and was never involved in the clinical management of any of the patients. Vessel quality was described as good, fair, or poor.

RESULTS

Increased age and poor vessel quality were the only significant predictors of poor outcome. Sex, presence or absence of angina, preoperative angina, preoperative ejection fraction, preoperative arrhythmia disorder, aortic cross-clamp time, and the number of bypass grafts had no significant effect on outcome in the perioperative period.

CONCLUSION

These results demonstrate that poor vessel quality and older age are predictors of poor outcome in patients with low ejection fractions undergoing myocardial revascularization. We conclude that poor distal coronary vasculature is a contraindication to coronary artery bypass grafting in patients with an ejection fraction of 0.25 or less, even if angina is present.

Left ventricular end-systolic volume index in patients with ischemic cardiomyopathy predicts postoperative ventricular function

BACKGROUND

We investigated the usefulness of the preoperative left ventricular end-systolic volume index (LVESVI) as a predictor of postoperative ventricular function.

METHODS

We retrospectively reviewed the records of 310 patients who underwent coronary artery bypass grafting and identified 20 patients with ischemic cardiomyopathy with a preoperative ejection fraction less than 0.30. We determined the preoperative and postoperative ejection fraction, LVESVI, and left ventricular enddiastolic volume index using biplane left cineventriculography. Patients were divided into groups depending on whether their preoperative LVESVI was less than 100 mL/m2 (group A, n = 10) or greater than 100 mL/m2 (group B, n = 10).

RESULTS

The mean ejection fraction increased significantly after coronary artery bypass grafting in group A from 0.25 +/- 0.05 to 0.40 +/- 0.09 (p < 0.01), but did not change significantly in group B (0.26 +/- 0.05 versus 0.23 +/- 0.06). The mean LVESVI decreased significantly in group A from 83.2 +/- 13.7 to 61.7 +/- 20.4 mL/m2 after operation (p < 0.05), but did not change significantly in group B (124.7 +/- 21.0 versus 121.5 +/- 37.6 mL/m2). In group B, 4 patients had signs of congestive heart failure during the follow-up period and had to be rehospitalized.

CONCLUSIONS

The mean ejection fraction improved significantly after coronary artery bypass grafting in patients with a preoperative LVESVI less than 100 mL/m2, despite the presence of a global left ventricular ejection fraction less than 0.30. Our results suggest that the preoperative LVESVI predicts the postoperative status and left ventricular function in patients with ischemic cardiomyopathy.