Isolated bypass grafting of the left internal thoracic artery to the left anterior descending coronary artery: late consequences of incomplete revascularization

Regenerative medicine for cardiovascular disorders-new milestones: adult stem cells

Cardiovascular disorders are the leading causes of mortality and morbidity in the developed world. Cell-based modalities have received considerable scientific attention over the last decade for their potential use in this clinical arena. This review was intended as a brief overview on the subject of therapeutic potential of adult stem cells in cardiovascular medicine with basic science findings and the current status of clinical applications. The historical perspective and basic concepts are reviewed and a description of current applications and potential adverse effects in cardiovascular medicine is given. Future improvements on cell-based therapies will likely provide remarkable improvement in survival and quality of life for millions of patients with cardiovascular disorders.

[Current evidence-based situation in coronary revascularization--CABG vs. PCI and diabetes?]

A variety of randomized, controlled trials comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) found similar results in mortality but significant differences in number of reinterventions in favor of CABG. This work gives an overview about the relevance and limitations of these studies in line with newly published large scale observational studies, which reveal significantly lower mortality-rates in CABG patients. Emphasis is placed on the special situation in the diabetic patient.

Incomplete revascularization during OPCAB surgery is associated with reduced mid-term event-free survival

BACKGROUND

The aim of this study was to compare early and mid-term outcome in patients undergoing off-pump coronary artery bypass surgery who have had complete revascularizations and incomplete revascularizations (IRs).

METHODS

Patient and operative data were collected prospectively for all patients who had off-pump coronary artery bypass surgery. Patients with multivessel disease were classified as having IR if the number of diseased coronary systems (left anterior descending coronary artery, circumflex and right coronary artery) exceeded the number of distal anastomoses. In-hospital outcomes, survival, and event-free survival were compared between patients with complete revascularization and IR using propensity scores to take account of differences in prognostic factors.

RESULTS

There were 1,479 off-pump coronary artery bypass surgery patients between April 1996 and December 2002 (30% of all coronary artery bypass graft patients), and 16.0% (237 patients) had IRs. Patients with IRs tended to be older and were female, had more extensive disease, worse dyspnea, a higher Parsonnet score, poorer ejection fraction, congestive cardiac failure, asthma or chronic obstructive airways disease, and previous cardiac surgery. The adjusted hazard ratio for patient survival with IRs versus complete revascularizations was 1.56 (95% confidence interval, 1.19 to 2.06; p = 0.001). Analyses for multiple time periods confirmed that IRs had a significantly increased risk of death, but also that the risk disappeared after the first 4 to 6 months of follow-up (p < 0.0001).

CONCLUSIONS

Compared with off-pump coronary artery bypass surgery patients with complete revascularizations, those with IRs have reduced survival, but only in the first 4 to 6 months after surgery. Patients' preoperative condition, rather than IR itself, may explain these findings because IRs should have mid-term as well as early effects.

Impact of Complete Revascularization on Long-Term Survival After Coronary Artery Bypass Grafting in Octogenarians

BACKGROUND

Complete revascularization is important in young patients undergoing coronary artery bypass grafting, but this principle remains less absolute in elderly patients. The purpose of this study was to determine how complete revascularization influenced long-term survival after coronary artery bypass grafting in octogenarians.

METHODS

From 1986 to 2003, 500 consecutive patients 80 to 94 years of age underwent coronary artery bypass grafting. Complete revascularization was defined as placement of at least one graft to each of the three major vascular regions that included a 50% diameter lesion. Revascularization was complete in 400 (80%) patients and incomplete in 100 (20%) patients. Mean (+/- standard deviation) follow-up was 51 +/- 41 months and was 99% complete (2,102 total patient-years).

RESULTS

Operative mortality was 8% +/- 2% (+/-95% confidence interval) and was statistically lower with complete (7% +/- 3%) versus incomplete (13% +/- 7%) revascularization (p < 0.05). Of 459 operative survivors, there were 261 late deaths. Multivariate regression analysis identified six independent predictors of late death: earlier operative year, male sex, peripheral or cerebrovascular disease, congestive heart failure, and incomplete revascularization (p < 0.03 for all). Excluding operative deaths, mean survival (Kaplan-Meier) was 82 months with complete revascularization compared with 65 months with incomplete revascularization (p < 0.008). Survival was 62% +/- 3% with complete versus 45% +/- 6% with incomplete revascularization at 5 years and 39% +/- 3% with complete versus 25% +/- 6% with incomplete revascularization at 8 years (p < 0.008).

CONCLUSIONS

In octogenarians undergoing coronary artery bypass grafting, complete revascularization correlated with improved long-term survival, increasing mean survival by almost 25% compared with incomplete revascularization.

Complete myocardial revascularization: between myth and reality

Myocardial revascularization in patients with multi-vessel coronary artery disease may be accomplished, by percutaneous interventions or surgery, either on all diseased lesions or directed to selectively targeted coronary segments. The extent of planned revascularization is often a major determinant of treatment strategy. Revascularization of all diseased coronary segments-complete myocardial revascularization-has a potential long-term benefit, but is more complex and may increase in-hospital untoward events. Revascularization may otherwise be incomplete, either because of the operator's inability to treat all diseased coronary segments or by choice of deciding to selectively revascularize only large areas of myocardium at risk. Although incomplete revascularization may negatively affect long-term outcomes, it may be, when wisely chosen, the preferred treatment strategy in selected patient categories because of its lower immediate risks. The patient's clinical status, ventricular function, and the presence of co-morbidities may orient clinical decisions in favour of incomplete revascularization.

Surgery is the best intervention for severe coronary artery disease

A multidisciplinary approach is essential, but best evidence favours surgery over percutaneous intervention

Protein-, gene-, and cell-based therapeutic angiogenesis for the treatment of myocardial ischemia

Therapeutic angiogenesis aims at restoring perfusion to chronically ischemic myocardial territories by using growth factors or cells, without intervening on the epicardial coronary arteries. Despite angiogenesis having received considerable scientific attention over the last decade, it has not yet been shown to provide clinical benefit and is still reserved for patients who have failed conventional therapies. Nevertheless, angiogenesis is a very potent physiologic process involved in the growth and development of every animal and human, and it is likely that its use for therapeutic purposes, once its underlying mechanistic basis is better understood, will one day become an important modality for patients with CAD and other types of organ ischemia. This review summarizes current knowledge in therapeutic angiogenesis research.

Development of pro-angiogenic engineered transcription factors for the treatment of cardiovascular disease

Gene therapies that use engineered transcription factors to regulate a patient's own endogenous genetic loci offer several advantages over cDNA-based approaches, including the capacity to upregulate all splice variants of a therapeutic gene. Currently, two engineered transcription factors are being developed for use in gene-mediated revascularisation therapies of cardiovascular disease. Both proteins target a powerful, constitutive transcriptional activation module to a defined sequence in the promoter region of vascular endothelial growth factor-A via linkage to an appropriately specific DNA-binding domain, either the basic helix-loop-helix motif of hypoxia-inducible factor-1alpha (HIF-1alpha) or a designed zinc finger protein. Both factors activate the expression of vascular endothelial growth factor-A in cellular studies and induce angiogenesis in animal models of cardiovascular disease. Phase I studies are underway for the HIF-1alpha-based factor and are expected to commence for the zinc finger protein-based factor by the second half of 2004.

Building In Vitro Models of Organs

Tissue-engineering techniques are being used to build in vitro models of organs as substitutes for human donor organs for transplantation as well as in vitro toxicology testing (as alternatives to use of animals). Tissue engineering involves the fabrication of scaffolds from materials that are biologically compatible to serve as cellular supports and microhabitats in order to reconstitute a desired tissue or organ. Three organ systems that are currently the foci of tissue engineering efforts for both transplantation and in vitro toxicology testing purposes are discussed. These are models of the cornea, nerves (peripheral nerves specifically), and cardiovascular components. In each of these organ systems, a variety of techniques and materials are being used to achieve the same end results. In general, models that are designed with consideration of the developmental and cellular biology of the target tissues or organs have tended to result in morphologically and physiologically accurate models. Many of the models, with further development and refinement, have the potential to be useful as functional substitute tissues and organs for transplantation or for in vitro toxicology testing.

Reoperative Coronary Artery Bypass Grafting: Analysis of Early and Late Outcomes

BACKGROUND

The purpose of this study was to evaluate early and late results of reoperative coronary artery bypass grafting compared with those of first coronary artery bypass grafting.

METHODS

From November 21, 1994, to December 31, 2001, 4,381 patients underwent isolated coronary revascularization: among these patients, 274 (6.3%) underwent a redo. Applying the propensity score, 239 redo patients (group R) were matched with 239 who underwent the first revascularization (group F).

RESULTS

Early mortality was 2.1% (group F) and 4.2% (group R), not significantly different. Group R showed significantly higher creatine kinase myocardial band release, length of intensive care unit stay, and incidence of incomplete myocardial revascularization than group F. In group R, off-pump patients showed higher incidence of incomplete revascularization. Redo was a risk factor for abnormal (>19 IU/L) creatine kinase myocardial band release (odds ratio, 1.7; p = 0.0066) and incomplete myocardial revascularization (odds ratio, 2.4; p = 0.0060). Five-year clinical outcome was significantly worse in group R, except for freedom from redo or percutaneous transluminal coronary angioplasty. Redo was an independent variable for lower freedom from death of any cause, cardiac death, acute myocardial infarction, cardiac events, and any event. Patients with higher creatine kinase myocardial band release or incomplete myocardial revascularization showed lower freedom from cardiac-related events. Incidence of incomplete myocardial revascularization and creatine kinase myocardial band release were significantly higher in group R by both univariate and multivariate analysis. This could explain the worse late outcome of redo patients.

CONCLUSIONS

Complete revascularization without damaging the heart, whichever technique is used, is the target of redo surgery, to achieve the same quality of results obtained in the first operation.

Papaverine Delivery to the Internal Mammary Artery Pedicle Effectively Treats Spasm

BACKGROUND

Left internal mammary artery spasm is well recognized during coronary artery bypass operations. Papaverine has been used by many surgeons to maximize mammary artery flow perioperatively, but the best delivery method is not known. We analyzed two techniques used at our institution.

METHODS

Fifty-eight patients were randomized into three groups to compare papaverine's ability to prevent spasm and to treat established spasm. Group 1 was control and no treatment was employed. In group 2, papaverine was injected with a blunt needle through the endothoracic fascia parallel to the mammary artery before harvest to assess spasm prevention. In group 3, papaverine was delivered perivascular in an identical manner to group 2 but after the mammary artery was dissected from the chest wall. This group was an evaluation of spasm treatment. Drug dosage was the same for both groups and routine bypass grafting was performed. Before anastomosing the mammary artery to the left anterior descending artery, blood flow was recorded for 15 seconds and flow per minute calculated. Cardiopulmonary bypass pressures were maintained at 70 mm Hg during collection.

RESULTS

Mean blood flows were: group 1 = 86.2 mL/min, group 2 = 122.5 mL/min, and group 3 = 139.7 mL/min. Left internal mammary artery flow in group 3 was statistically different from control (p = 0.0457). Group 2 flow approached but did not reach statistical significance (p = 0.0874). Mammary artery dissection times for the three groups were not different.

CONCLUSIONS

Papaverine delivery to the left internal mammary artery after dissection treats spasm effectively, improves blood flow at the time of its anastamosis to the left anterior descending artery, and avoids any risk of intimal injury. Injection of papaverine before mammary artery harvest does not shorten dissection time, and flow is not statistically improved.

Impact of multivessel coronary artery disease on outcome after isolated minimally invasive bypass grafting of the left anterior descending artery

BACKGROUND

The outcome in patients treated surgically for coronary artery disease is known to be influenced by the extent of the disease. Whether this factor also has an effect in patients undergoing isolated minimally invasive revascularization of the left anterior descending (LAD) artery using the internal thoracic artery (ITA) (MIDCAB) has not been looked at. Thus, this study sought to evaluate the impact of multivessel disease (MVD) on midterm outcome after MIDCAB.

METHODS

From 1996 to 1999, 411 patients received a MIDCAB at our institution and were now followed up. Isolated disease of the LAD (SVD -single vessel disease) was presented in 262 patients (63.7%) and 149 patients (36.3%) had MVD at the time of operation. The reasons for apparent incomplete revascularization in patients with MVD were very small target vessels (< 1.0-mm diameter), stenoses of less than 50%, distal localization of the stenoses, long-term patency after angioplasty, or an extensive risk for sternotomy and(or) cardiopulmonary bypass. The midterm outcome was evaluated by questionnaires sent to the patients and their physicians.

RESULTS

The mean follow-up was 29.4 +/- 11.1 months. The incidence of myocardial infarction was significantly higher in MVD as compared to SVD patients (8.1% vs 1.9%, p = 0.04). Patients with MVD had significantly more subsequent percutaneous transluminal coronary angioplasty (10.7% vs 5.3%, p = 0.049) and a similar number of repeat surgical revascularizations as compared to SVD patients. Patients with MVD had a significantly higher total 3-year mortality as compared to SVD patients by Kaplan-Meier estimate (8.7% vs 3.1%, relative risk [RR] = 2.56, p = 0.011). The 3-year cardiac mortality was significantly higher in patients with MVD as compared to SVD (4.0% vs 0.4%, RR = 9.48, p = 0.0054). After adjustment of baseline characteristics by Cox regression analysis, the 3-year risk of cardiac death was significantly higher in the MVD groups (RR = 2.2, confidence interval [CI] 95%: 1.8 to 4.65, p = 0.029).

CONCLUSIONS

Patients with isolated disease of the LAD appear to benefit from ITA grafting in the form of a MIDCAB procedure. Here, it should be an approach of choice. The results show that MVD is an independent risk factor for outcome in patients undergoing a MIDCAB procedure. Nevertheless, the midterm morbidity and mortality in MVD patients after a MIDCAB procedure where the LAD is the only target vessel for interventional or surgical treatment is acceptable despite a higher morbidity than in SVD patients.

Impact of diabetes on outcome following isolated minimally invasive bypass grafting of the left anterior descending artery

BACKGROUND

The outcome in patients treated by conventional coronary artery bypass grafting (CABG) for coronary artery disease is negatively influenced by the presence of diabetes. The relative effect of diabetes in patients undergoing isolated minimally invasive revascularization of the left anterior descending artery (LAD) using the internal thoracic artery (ITA) has as yet not specifically been looked at. Thus, this study sought to evaluate the impact of diabetes on mid-term outcome following minimally invasive coronary artery bypass grafting (MIDCAB).

METHODS

From 1996 to 1999, 411 patients received a MIDCAB procedure at our institution and were now followed up. In this study population there were 63 diabetic patients (15.3%) and 348 nondiabetic patients (84.7%). Isolated proximal stenoses or an occlusion of the LAD were present in 262 patients (63.7%), whereas 149 (36.3%) had multi-vessel disease (MVD) at the time of the MIDCAB procedure. The clinical outcome was evaluated by questionnaires sent to the patients and their physicians.

RESULTS

The mean follow-up was 29.4 +/- 11.1 months. The incidence of myocardial infarction was significantly higher in diabetics as compared to nondiabetics (9.5% vs 3.2%, p = 0.034). Diabetics and nondiabetics had similar rates of subsequent revascularization procedures during follow-up. Cumulative total survival of diabetic and nondiabetic patients was not statistically different. The 3-year cardiac mortality was however significantly higher in diabetic than in nondiabetic patients if MVD was initially present (Kaplan-Meier estimate: 10.7% vs 2.5%, relative risk [RR] = 5.5, p = 0.017 by log-rank test). The 3-year cardiac mortality in diabetic and nondiabetic patients with isolated disease of the LAD (single vessel disease [SVD]) was not significantly different. After adjustment of baseline characteristics by Cox regression analysis the 3-year risk of cardiac death was significantly higher in the diabetic group (RR = 1.82, CI 95%:1.2 to 3.3, p = 0.045).

CONCLUSIONS

The results support diabetes to be an independent risk factor for outcome in patients with MVD undergoing a MIDCAB procedure in analogy to those undergoing CABG procedures. Diabetics with isolated disease of the LAD, however, benefit out of proportion from this treatment modality.

Comparison of off-pump and on-pump coronary artery bypass grafting in midterm results

OBJECTIVE

Off-pump coronary artery bypass grafting (OPCAB) has become a procedure of choice for surgical treatment of coronary artery disease. Although early advantages of OPCAB were confirmed in comparison with conventional on-pump coronary artery bypass grafting (CABG), late cardiac complications are still controversial. We examined midterm results of OPCAB compared with standard CABG.

METHODS

Between July 1997 and April 2002, 736 consecutive patients who underwent isolated CABG were retrospectively reviewed. The OPCAB group (Group I) comprised 357 patients (49%), and the on-pump CABG group (Group II) 379 patients (51%). Their preoperative, intraoperative, and follow-up data were analyzed.

RESULTS

The mean number of distal anastomoses and the early graft patency were not greatly different between the two groups. The actuarial survival rate at 3 years was not significantly different between Group I (98.3%) and Group II (98.2%) (p = 0.71). The frequency of cardiac events was 4.2%/patient-year in Group I and 2.6%/patient-year in Group II (p = 0.12). The actuarial event free rates were not different between the two groups (p = 0.61). The cardiac event free rates at 3 years were significantly (p = 0.011) higher in patients with complete revascularization (96.7%) than without complete revascularization in Group I (69.2%) and in Group II (92.7% versus 85.9%, p = 0.026).

CONCLUSIONS

Midterm clinical outcome in OPCAB is as good as conventional on-pump CABG. Incomplete revascularization caused cardiac events more frequently than complete revascularization both in OPCAB and on-pump CABG in the intermediate follow-up.

Revascularization of multiple bypassable extended right coronary arteries

BACKGROUND

Extended right coronary arteries are not uncommon in coronary surgery. They can be revascularized optionally either by conventional single or complete multiple bypassing. However, there are still no objective data showing the superiority or appropriateness of one of these methods over the other.

METHODS

Extended right coronary arteries were identified by preoperative angiographic scoring and randomized to multiple-bypassing (group A; n = 32) or single-bypassing (group B; n = 32) groups. Four parameters that show the completeness of right coronary territory revascularization were evaluated and compared between the 2 groups.

RESULTS

Although overall perioperative ischemic events seemed to increase in the single-bypass group (P =.0059), half of them were reversible, and there were no statistical differences between the definitive perioperative ischemic event rates, namely, infarction rates, and the remaining 3 parameters of the groups. Logistic regression analysis showed that preoperative left ventricular dysfunction (ejection fraction <50%) was the most significant predictor of these perioperative ischemic events. Hence, the subgroups of patients with left ventricular dysfunction were also evaluated (subgroup A, n =13; subgroup B, n = 12). Overall perioperative ischemic event (P =.001), definitive perioperative ischemic event (infarction; P =.0324), and consequent right ventricular dysfunction (P =.0324) rates were significantly higher in the single-bypass subgroup. Postoperative reperfusion status and graft patency rates of the right coronary territory did not change with the different revascularization methods.

CONCLUSIONS

Complete revascularization of extended right coronary arteries did not seem advantageous over its conventional operation in patients with normal ventricular function; however, in patients with poor ventricular function (ejection fraction <50%), it prevented perioperative ischemic events in the right coronary territory and the consequent functional impairment that appeared with conventional operation.

Effect of surgical revascularization of a right coronary artery tributary of an infarcted nonischemic territory on the outcome of patients with three-vessel disease: a prospective randomized trial

BACKGROUND

We evaluated the in-hospital and long-term effects of surgical grafting of a dominant graftable right coronary artery tributary of an infarcted nonischemic territory in patients with triple-vessel disease who were undergoing coronary artery bypass grafting.

METHODS

Of 303 consecutive patients undergoing coronary artery bypass grafting with 3-vessel coronary disease and a dominant right coronary artery tributary of an infarcted nonischemic territory, 154 were randomized to right coronary artery revascularization and 149 to no right coronary artery grafting. In all cases, standard on-pump surgical myocardial revascularization was performed.

RESULTS

Overall hospital mortality was 2 of 154 versus 1 of 149 (P =.97); no difference in in-hospital outcome was observed between the 2 groups. At follow-up, cardiac event-free survival was 84 of 152 in the right coronary artery grafting series and 62 of 148 in the non-right coronary artery grafting group (P =.20). However, when the analysis was limited to surviving patients without new scintigraphic evidence of ischemia (to avoid confounding factors derived from ischemia in the left coronary system or right coronary artery graft malfunction), we found that patients who received a right coronary artery graft had fewer cardiac events, a lower incidence of arrhythmia, and less left ventricular dilatation than did the non-right coronary artery revascularized series.

CONCLUSIONS

Surgical grafting of a right coronary artery tributary of an infarcted nonischemic territory in patients with 3-vessel coronary artery disease submitted to coronary artery bypass grafting improved late electric stability, ventricular geometry, and event-free survival but did not affect in-hospital or 10-year survival.

Equivalent midterm outcomes after off-pump and on-pump coronary surgery

OBJECTIVE

Multiple reports demonstrate that off-pump surgery reduces the early morbidity associated with coronary artery bypass grafting. To determine if there are any differences in later outcomes, we compared midterm results of propensity-matched patients who underwent off- and on-pump coronary artery bypass grafting.

METHODS

From January 1997 to July 2000, 481 patients underwent off-pump coronary artery bypass grafting and 3231 underwent on-pump coronary artery bypass grafting. Propensity matching was used to match 406 patients from each group. Previously, the propensity-matched off-pump patients were found to have had significantly fewer bypass grafts. These 812 patients were followed for time-related events, including death, myocardial infarction, percutaneous coronary intervention, coronary reoperation, and the combined end point of all-cause mortality, myocardial infarction, and all coronary reintervention. Follow-up was 95% complete.

RESULTS

At 4 years, survival was 87.5% after off-pump and 91.2% after on-pump coronary artery bypass grafting (P =.2); freedom from myocardial infarction was 92.6% and 95.7% (P =.7), respectively; freedom from percutaneous coronary intervention was 94.3% and 95.5% (P =.9), respectively; freedom from coronary reoperation was 98.1% and 99.0% (P =.4), respectively; and freedom from the combined end point of all-cause mortality, myocardial infarction, and coronary reintervention was 75.2% and 82.9% (P =.14), respectively.

CONCLUSIONS

Off-pump and on-pump coronary artery bypass grafting results in equivalent midterm outcomes. Fewer bypass grafts in the off-pump patients did not decrease survival or increase ischemic events at 4 years.

Angiogenic protein therapy

Therapeutic angiogenesis, in the form of growth factor protein administration or gene therapy, has emerged as a new method of treatment for patients with severe, inoperable coronary artery disease. Improved myocardial perfusion and function after the administration of angiogenic growth factors has been demonstrated in animal models of chronic myocardial ischemia. A recent clinical study reported beneficial long-term effects of therapeutic angiogenesis using FGF-2 protein in terms of freedom from angina and myocardial perfusion on nuclear imaging and suggested that protein angiogenic therapy has the potential to extend treatment options to patients who are not optimal candidates for conventional methods of myocardial revascularization. The ultimate role that angiogenesis will play in the treatment of ischemic heart disease will, however, be determined from adequately powered, randomized, double-blind, placebo-controlled trials. It is likely that endogenous antiangiogenic influences, intrinsic lack of response of patients with severe endothelial dysfunction, and other limitations will have to be overcome before angiogenesis becomes standard therapy for the treatment of coronary artery disease.

Coronary reoperations: recurrence of angina and clinical outcome with and without cardiopulmonary bypass

BACKGROUND

We compared our experience of minimal tissue dissection and target vessel revascularization without cardiopulmonary bypass (CPB) with the standard procedure of total dissection of the heart and complete revascularization with CPB in patients who had elective reoperative coronary artery bypass grafting (redo-CABG).

METHODS

We analyzed recurrence of angina and clinical outcome in 118 patients who had elective redo-CABG between January 1995 and April 2002. Seventy-four patients had redo-CABG with CPB, and 44 patients had redo-CABG without CPB.

RESULTS

Perioperative outcome was comparable with regard to morbidity and mortality rates. At follow-up, the mean Canadian Cardiovascular Society score was 1.3 +/- 0.6 in patients who had redo-CABG with CPB and 1.7 +/- 0.8 in patients who had redo-CABG without CPB (p = 0.02). At follow-up, patients who had redo-CABG without CPB had a higher rate of recurrence of angina (log rank = 0.001) and higher use of nitrates (p = 0.015). Target vessel revascularization was an independent predictor of recurrence of angina in younger patients (< 75 years; p = 0.012) but not in the elderly (> or = 75 years; p = 0.142).

CONCLUSIONS

In elective redo-CABG patients, minimal tissue dissection and target vessel revascularization without cardiopulmonary bypass did not add significant benefit with regard to perioperative morbidity and mortality. The unsatisfactory relief of symptoms does not seem to justify target vessel revascularization by a less invasive approach. Therefore, this technique should be offered exclusively to patients at high risk with complete revascularization using CPB, such as the elderly.

Vascular growth factors and angiogenesis in cardiac surgery

Therapeutic angiogenesis, in the form of growth factor protein administration or gene therapy, has emerged as a new method of treatment for patients with severe, inoperable coronary artery disease. Improved myocardial perfusion and function after administration of angiogenic growth factors has been demonstrated in animal models of chronic myocardial ischemia. Recently, preliminary clinical trials using growth factor proteins or genes encoding these angiogenic factors have demonstrated clinical and other objective evidence of relevant angiogenesis. A recent study reported beneficial long-term effects of therapeutic angiogenesis using fibroblast growth factor (FGF)-2 protein in terms of freedom from angina and perfusion on single-photon emission computed tomographic imaging. Thus, therapeutic angiogenesis has the potential to extend treatment options to patients who are not optimal candidates for conventional methods of myocardial revascularization. However, endogenous antiangiogenic influences, intrinsic lack of response of patients with severe endothelial dysfunction, and other limitations will need to be overcome before angiogenesis becomes a standard therapy for the treatment of patients with severe coronary disease.

Beyond complete myocardial revascularization: is it important and does it matter?

Constructing more than one graft per coronary system (left anterior descending, circumflex, right) has been widely and enthusiastically practiced for many years because it was thought to confer long-term freedom from major adverse coronary events. In reality the medical and surgical literature do not document the importance of maximizing the number of coronary vessels bypassed beyond one per system. Published series exhibit great variation in patient cohort, length of follow-up and lack the whole gamut of clinical endpoints. None of the published series provide an analysis based on subset stratification according to detailed coronary vessel anatomopathologic inventory in relation to revascularization strategy.

Coronary revascularization in the 21st century. Emphasis on contributions by Japanese surgeons

The first three decades of coronary artery surgery have provided the foundation for the next century of this evolution. It is apparent that a multitude of events including the development of cardioplegia, improving surgical instrumentation, technological advances including endoscopic approaches and computer assisted robotics and biologic discoveries such as the role of the endothelium have provided the underpinnings for improved surgical outcomes. However, the single most important determinant of late results is the type of bypass conduit used for grafting. Thus, use of the left internal thoracic artery (ITA) grafted to the left anterior descending coronary is a more important determinant of survival than is any other factor (progression of coronary artery disease, increased age, poor left ventricular function, diabetes, female gender and off-pump operations). Use of two ITAs provides further benefit and it is likely that three or more arterial conduits will be shown to be advantageous in this regard in due time. Japanese cardiothoracic surgeons have made significant contributions to the continuing evolution of coronary bypass surgery and particularly to the advance of arterial conduits. This report will address those contributions to this evolution.

Does off-pump coronary surgery reduce morbidity and mortality?

OBJECTIVE

To compare hospital outcomes of on-pump and off-pump coronary artery bypass surgery.

METHODS

From 1997 to 2000, primary coronary artery bypass grafting was performed in 481 patients off pump and in 3231 patients on pump. Hospital outcomes were compared between propensity-matched pairs of 406 on-pump and 406 off-pump patients. The 2 groups were similar in age (P =.9), left ventricular function (P =.7), extent of coronary artery disease (P =.5), carotid artery disease (P =.4), and chronic obstructive pulmonary disease (P =.5). However, off-pump patients had more previous strokes (P =.05) and peripheral vascular disease (P =.02); on-pump patients had a higher preoperative New York Heart Association class (P =.01).

RESULTS

In the matched pairs the mean number of bypass grafts was 2.8 +/- 1.0 in off-pump patients and 3.5 +/- 1.1 in on-pump patients (P <.001). Fewer grafts were performed to the circumflex (P <.001) and right coronary (P =.006) artery systems in the off-pump patients. Postoperative mortality, stroke, myocardial infarction, and reoperation for bleeding were similar in the 2 groups. There was more encephalopathy (P =.02), sternal wound infection (P =.04), red blood cell use (P =.002), and renal failure requiring dialysis (P =.03) in the on-pump patients.

CONCLUSIONS

Both off- and on-pump procedures produced excellent early clinical results with low mortality. An advantage of an off-pump operation was less postoperative morbidity; however, less complete revascularization introduced uncertainty about late results. A disadvantage of on-pump bypass was higher morbidity that seemed attributable to cardiopulmonary bypass.

Conversion to off-pump coronary bypass without increased morbidity or change in practice

BACKGROUND

This article examines the feasibility of complete conversion from conventional coronary artery operation to routine off-pump coronary bypass operation.

METHODS

Data on our first 285 off-pump procedures using the Octopus system (Medtronic Inc, Minneapolis, MN) represent our learning curve. This is a complete experience in coronary bypass surgery over 16 months.

RESULTS

The cohort was nonselected. All patients had at least two-vessel disease. Eight hundred seven grafts were performed (mean, 2.8 per patient) of which 647 grafts (84%) were arterial (mean, 2.3 per patient). One hundred seventy nine patients (63%) underwent total arterial revascularization. Eight patients required cardiopulmonary bypass; all other operations were completed off-pump. Complications were: mortality, 3 patients (1.5%); renal failure, 24 patients (8%); stroke, 2 patients (< 1%); and atrial fibrillation, 60 patients (21%). The morbidity data and frequency of arterial grafting did not differ from that of 355 patients who underwent coronary bypass operations in a preceding 18-month period.

CONCLUSIONS

Complete shift from routine use of cardiopulmonary bypass to nonselective off-pump coronary bypass operation is possible with a low conversion rate and without an apparent increase in morbidity or change in technique. Whereas short-term safety and efficacy seem certain, studies of long-term outcome are necessary before the eventual role of off-pump coronary bypass in myocardial revascularization can be defined.

Minimally invasive single-vessel coronary artery bypass with the internal thoracic artery and early postoperative angiography: midterm results of a prospective study in 120 consecutive patients

BACKGROUND

This prospective study was undertaken to determine the role of the minimally invasive direct coronary artery bypass with early postoperative angiography and midterm follow-up in 120 consecutive patients with single-vessel coronary artery disease.

METHODS

Minimal access (6 to 10 cm), without complete sternotomy and no cardiopulmonary bypass, was used. The lesions were located at the proximal left anterior descending coronary artery in 95% of the patients. Routine coronary angiography was performed before discharge.

RESULTS

Postoperative angiography was performed in 104 (90.4%) of those 115 patients who had coronary revascularization concluded by the mini-access method. The internal thoracic artery patency rate was 98.1% (95.2% grade A). Two (1.7%) patients presented with perioperative myocardial infarction, which led to the single in-hospital death (0.8%). Of the remaining 119 patients, 113 (95.0%) were asymptomatic. The event-free probability was 94.9% and the actuarial survival was 98.3% with 42 months of follow-up.

CONCLUSIONS

For selected patients with single-vessel coronary artery disease and no major myocardial dysfunction, minimally invasive direct coronary artery bypass is a safe operation and a less invasive alternative to conventional coronary artery bypass grafting.

Influence of internal mammary artery grafting and completeness of revascularization on long-term outcome in octogenarians

BACKGROUND

It has been well established that complete revascularization with internal mammary artery (IMA) grafting is important in young patients undergoing coronary artery bypass grafting (CABG). Applying these principles to octogenarians remains controversial.

METHODS

From 1986 to 1999, 358 consecutive patients aged 80 to 94 years underwent CABG. Revascularization was complete in 291 (81%) and incomplete in 67 (19%). The IMA was used in 231 (65%) cases.

RESULTS

Operative mortality was 7% +/- 1%, but was not statistically different with or without IMA grafting (IMA 5% +/- 2% versus no IMA 10% +/- 3%, p = 0.11) or complete revascularization (p > 0.41). Midterm survival improved with IMA grafting (70% +/- 3% versus 56% +/- 5% at 4 years, p < 0.03; 36% +/- 4% versus 29% +/- 5% at 8 years, p < 0.08), but was not significant beyond 8 years. Among 138 survivors, those with IMA grafts were more likely to be angina free (82% versus 53%, p < 0.001) and in New York Heart Association class I (60% versus 36%, p < 0.03). Survival, recurrent angina, and functional class were independent of completeness of revascularization (p > 0.21).

CONCLUSIONS

IMA grafting improved survival, angina, and functional class of octogenarians, but complete revascularization did not have a similar impact.