Acute coronary insufficiency (impending myocardial infarction and myocardial infarction): surgical treatment by the saphenous vein graft technique

A Novel Method to Determine the Cause of Left Internal Mammary Artery Instant Non-Patency Based on Transit Time Flow Measurement

Objective: After coronary artery bypass grafting (CABG) surgery, the main causes of poor instant patency of left internal mammary arteries (LIMAs) are competitive flow and anastomotic stenosis, but how to determine the cause of LIMA non-patency without interfering with the native coronary artery is still a difficult problem to be solved urgently.

Methods: In this study, a 0D-3D coupled multiscaled CABG model of anastomotic stenosis and competitive flow was constructed. After calculation, the flow waveform of the LIMA was extracted, and the waveform shape, common clinical parameters (average flow, PI, and DF), and graft flow FFT ratio results (F0/H1 and F0/H2) were analyzed.

Results: For LIMA, these three common clinical parameters did not differ significantly between the anastomotic stenosis group and competitive flow group. However, the waveform shape and FFT ratio (especially F0/H2) of the competitive flow group were significantly different from those of the anastomotic stenosis group. When the cause was competitive flow, there was systolic backflow, and F0/H2 was too high (>14.89). When the cause was anastomotic stenosis, the waveform maintained a bimodal state and F0/H2 was in a normal state (about 1.17).

Conclusion: When poor instant patency of the LIMA is found after CABG, the causes can be determined by graft flow waveform shape and F0/H2.

Bioengineering Human Tissues and the Future of Vascular Replacement

Cardiovascular defects, injuries, and degenerative diseases often require surgical intervention and the use of implantable replacement material and conduits. Traditional vascular grafts made of synthetic polymers, animal and cadaveric tissues, or autologous vasculature have been utilized for almost a century with well-characterized outcomes, leaving areas of unmet need for the patients in terms of durability and long-term patency, susceptibility to infection, immunogenicity associated with the risk of rejection, and inflammation and mechanical failure. Research to address these limitations is exploring avenues as diverse as gene therapy, cell therapy, cell reprogramming, and bioengineering of human tissue and replacement organs. Tissue-engineered vascular conduits, either with viable autologous cells or decellularized, are the forefront of technology in cardiovascular reconstruction and offer many benefits over traditional graft materials, particularly in the potential for the implanted material to be adopted and remodeled into host tissue and thus offer safer, more durable performance. This review discusses the key advances and future directions in the field of surgical vascular repair, replacement, and reconstruction, with a focus on the challenges and expected benefits of bioengineering human tissues and blood vessels.

Potential Beneficial Effects of Vitamin D in Coronary Artery Disease

Vitamin D plays a pivotal role in bone homeostasis and calcium metabolism. However, recent research has indicated additional beneficial effects of vitamin D on the cardiovascular system. This review aims to elucidate if vitamin D can be used as an add-on treatment in coronary artery disease (CAD). Large-scale epidemiological studies have found a significant inverse association between serum 25(OH)-vitamin D levels and the prevalence of essential hypertension. Likewise, epidemiological data have suggested plasma levels of vitamin D to be inversely correlated to cardiac injury after acute myocardial infarction (MI). Remarkably, in vitro trials have showed that vitamin D can actively suppress the intracellular NF-κB pathway to decrease CAD progression. This is suggested as a mechanistic link to explain how vitamin D may decrease vascular inflammation and atherosclerosis. A review of randomized controlled trials with vitamin D supplementation showed ambiguous results. This may partly be explained by heterogeneous study groups. It is suggested that subgroups of diabetic patients may benefit more from vitamin D supplementation. Moreover, some studies have indicated that calcitriol rather than cholecalciferol exerts more potent beneficial effects on atherosclerosis and CAD. Therefore, further studies are required to clarify these assumptions.

The development and mechanical characterisation of a novel reinforced venous conduit that mimics the mechanical properties of an arterial wall

Venous grafts have been used to bypass stenotic arteries for many decades. However, this "gold standard" treatment is far from optimal, with long-term vein graft patency rates reported to be as low as 50% at >15 years. These results could be a result of the structural and functional differences of veins compared to arteries. In this study we developed a new protocol for manufacturing reinforced fresh veins with a decellularized porcine arterial scaffold. This novel method was designed to be replicated easily in a surgical setting, and manufactured reinforced constructs were robust and easier to handle than the veins alone. Furthermore, we demonstrate that these Reinforced Venous-Arterial Conduits have comparable mechanical properties to native arteries, in terms of ultimate tensile strength (UTS) (2.36 vs. 2.24MPa) and collagen dominant phase (11.04 vs. 12.26MPa). Therefore, the Reinforced Venous-Arterial Conduit combines the benefits of using the current gold standard homogenous venous grafts composed of a confluent endothelial surface, with an "off-the-shelf" decellularized artery to improve the mechanical properties to closely mimic those of native arteries, while maintaining the self-repairing characteristics of native tissue. In conclusion in this study we have produced a construct and a new technique that combines the mechanical properties of both a natural vein and a decellularized artery to produce a reinforced venous graft that closely mimics the mechanical response of an arterial segment.

[Coronary artery bypass graft surgery with bilateral internal mammary artery. Short-term results]

INTRODUCTION

Coronary artery bypass graft (CABG) surgery remains the reference standard in the treatment of multivessel coronary disease. Several studies have shown that CABG with bilateral internal mammary arteries (BIMA) has better results in long-term survival.

METHODOLOGY

A retrospective study was conducted on CABG surgeries with BIMA from January 2012 to December 2015 in the National Cardiovascular Institute, INCOR, EsSalud, Peru. The objectives were to determine the mortality and major cardiovascular events at 30 days follow-up.

RESULTS

Of the 36 patients subjected to CABG surgery with BIMA, the 30-day mortality was 0%, with major cardiovascular events occurring in 5.56% of patients (Stroke 0%, postoperative myocardial infarction 5.56%, need of new coronary intervention 0%). The incidence of mediastinitis and/or sternal reconstruction was 0%. Superficial wound infection was observed in 7 patients, with there being no significant difference between diabetics and non-diabetics (25% vs. 16.66%, OR=3.3, P=.88), or between patients with or without overweight (19.23% vs. 20%, respectively, OR=.95; 95% CI, P=.68).

CONCLUSIONS

CABG surgery with BIMA is a safe procedure, with low rates of mortality and major cardiovascular events in the short-term.

Percutaneous Mechanical Reperfusion During Acute Myocardial Infarction

The treatment of acute myocardial infarction has progressed from bedrest to mechanical, catheter-based reperfusion. The authors review the use of percutaneous coronary intervention (PCI) as a primary treatment for acute myocardial infarction and the use of adjunctive agents. The most recent American College of Cardiology/ American Heart Association (ACC/AHA) guidelines for the use of PCI in ST segment elevation myocardial infarction (MI) advocate the use of PCI as primary therapy at those centers in which the procedure can be performed within accepted standards. Because a majority of hospitals (80%) do not have the capability of performing primary PCI, most patients are treated with thrombolytic therapy. PCI should be considered in those patients treated with thrombolytic therapy who have persistent or recurrent ischemia and/or cardiogenic shock. For patients with non-ST elevation MI, the use of an invasive strategy (early angiography and PCI if needed) has recently shown to be beneficial. Although revascularization is the basis of the acute therapy of MI, additional pharmacologic therapy in the acute setting is now recognized as a key to favorable long-term outcome.

Reperfusion therapy for acute myocardial infarction: Concepts and controversies from inception to acceptance

More than 20 years of misconceptions derailed acceptance of reperfusion therapy for acute myocardial infarction (AMI). Cardiologists abandoned reperfusion for AMI using fibrinolytic therapy, explored in 1958, because they no longer attributed myocardial infarction to coronary thrombosis. Emergent aortocoronary bypass surgery, pioneered in 1968, remained controversial because of the misconception that hemorrhage into reperfused myocardium would result in infarct extension. Attempts to limit infarct size by pharmacotherapy without reperfusion dominated research in the 1970s. Myocardial necrosis was assumed to progress slowly, in a lateral direction. At least 18 hours was believed to be available for myocardial salvage. Afterload reduction and improvement of the microcirculation, but not reperfusion, were thought to provide the benefit of streptokinase therapy. Finally, coronary vasospasm was hypothesized to be the central mechanism in the pathogenesis of AMI. These misconceptions unraveled in the late 1970s. Myocardial necrosis was shown to progress in a transmural direction, as a "wave front," beginning with the subendocardium. Reperfusion within 6 hours salvaged a subepicardial ischemic zone in experimental animals. Acute angiography provided in vivo evidence of the high incidence of total coronary occlusion in the first hours of AMI. In 1978, early reperfusion by transluminal recanalization was shown to be feasible. The pathogenetic role of coronary thrombosis was definitively established in 1979 by demonstrating that intracoronary streptokinase rapidly restored flow in occluded infarct-related arteries, in contrast to intracoronary nitroglycerine which rarely did. The modern reperfusion era had dawned.

Saphenous Vein Graft Disease Is Associated with a Low Serum Erythropoietin Level

OBJECTIVE

To measure the serum erythropoietin (EPO) level in patients with saphenous vein grafts (SVGs) and to compare the EPO level in those with and without SVG disease.

SUBJECTS AND METHODS

The study included 85 consecutive patients with a history of coronary artery bypass graft surgery that underwent elective coronary angiography. Patients with >30% stenosis (diseased grafts) in at least one saphenous graft were included in group 1 (diseased group: n = 40), and group 2 (nondiseased group: n = 45) consisted of patients without diseased SVGs. The EPO level was measured using enzyme-linked immunosorbent assay (ELISA) using a commercially available ELISA kit; x03C7;2 test and independent samples t test were used where appropriate. Logistic regression was used for multivariate analysis.

RESULTS

There were not any significant differences in age, gender, or cardiovascular risk factors between the two groups except for increased triglyceride and low high-density lipoprotein levels in group 2. The EPO level was significantly higher in the nondiseased SVG group than in the diseased SVG group (25.5 ± 9.6 vs. 17.8 ± 6.8 mU ml-1, p = 0.002). Multivariate logistic regression analysis showed that the serum EPO level was an independent predictor of SVG disease (OR 1.14, 95% CI 1.06-1.24, p = 0.001).

CONCLUSION

In this study, SVG disease was associated with a low serum EPO level, suggesting that a low EPO level could be predictive of and contributes to the pathophysiology of SVG disease.

A meta-analysis of randomized controlled trials on mid-term angiographic outcomes for radial artery versus saphenous vein in coronary artery bypass graft surgery

BACKGROUND

Currently, saphenous vein (SV) and radial artery (RA) are the most commonly used conduits in combination with the left internal mammary artery for conventional coronary artery bypass graft surgery (CABG). The present meta-analysis aimed to assess the existing evidence from randomized controlled trials (RCTs) to compare the angiographic outcomes of these two conduits at mid-term follow-up.

METHODS

Four relevant and updated RCTs with follow-up beyond 3 years were identified using five electronic databases. Angiographic endpoints included complete occlusion, 'string sign', graft failure and complete patency.

RESULTS

The incidence of complete occlusion was significantly lower after using RA compared to SV [6.7% vs. 17.2%; odd ratio (OR), 0.36; 95% confidence interval (CI), 0.23-0.58; P<0.0001]. The angiographic 'string sign' was significantly more likely to be identified after using RA compared to SV (3.1% vs. 0%; OR, 5.65; 95% CI, 1.21-26.39; P=0.03). Graft failure was significantly lower after RA compared to SV (9.6% vs. 18.8%; OR, 0.47; 95% CI, 0.30-0.72; P=0.0005). Complete graft patency was found to be significantly higher after RA compared to SV (88.6% vs. 75.8%; OR, 3.19; 95% CI, 1.42-7.16; P=0.005).

CONCLUSIONS

Results of the present meta-analysis suggest that selected patients with severe, proximal stenosis may have superior angiographic outcomes at mid-term follow-up after using RA compared to SV for CABG. However, RA is associated with a significantly higher incidence of the 'string sign'. Future studies should aim to collect additional data on symptomatic outcomes.

Immediate surgical coronary revascularisation in patients presenting with acute myocardial infarction

Background

The number of patients presenting with acute myocardial infarction (AMI) and being untreatable by interventional cardiologists increased during the last years. Previous experience in emergency coronary artery bypass grafting (CABG) in these patients spurred us towards a more liberal acceptance for surgery. Following a prospective protocol, patients were operated on and further analysed.

Methods

Within a two year interval, 127 patients (38 female, age 68±12 years, EuroScore (ES) II 6.7±7.2%) presenting with AMI (86 non-ST-elevated myocardial infarction (NSTEMI), 41 STEMI) were immediately accepted for emergency CABG and operated on within six hours after cardiac catheterisation (77% three-vessel-disease, 47% left main stem stenosis, 11% cardiogenic shock, 21% preoperative intraaortic balloon pump (IABP), left ventricular ejection fraction 48±15%).

Results

30-day-mortality was 6% (8 patients, 2 NSTEMI (2%) 6 STEMI (15%), p=0.014). Complete revascularisation could be achieved in 80% of the patients using 2±1 grafts and 3±1 distal anastomoses. In total, 66% were supported by IABP, extracorporal life support (ECLS) systems were implanted in two patients. Logistic regression analysis revealed the ES II as an independent risk factor for mortality (p<0.001, HR 1.216, 95%-CI-Intervall 1.082-1.366).

Conclusions

Quo ad vitam, results of emergency CABG for patients presenting with NSTEMI can be compared with those of elective revascularisation. Complete revascularisation obviously offers a clear benefit for the patients. Mortality in patients presenting with STEMI and cardiogenic shock is substantially high. For these patients, other concepts regarding timing of surgical revascularisation and bridging until surgery need to be taken into consideration.

Endoscopic vein harvesting is influenced by patient-related risk factors and may be of specific benefit in female patients

OBJECTIVES

The standard of care regarding endoscopic vein harvesting (EVH) is still inhomogeneous across Europe. The current study aimed at elucidating patient-related factors favouring its application and procedure-related outcome in a tertiary care centre.

METHODS

All patients who underwent coronary artery bypass grafting with or without concomitant valve procedures between 2008 and 2011 were included. Emergency surgery and all arterial revascularization patients were excluded.

RESULTS

A total of 262 endoscopically harvested patients and 623 open vein harvested patients were included. Mortality, perfusion time and cross-clamp time were not significantly different. Peripheral artery disease predisposed open vein harvesting (odds ratio [OR] 1.9; P = 0.001); diabetes and a higher number of diseased coronary vessels favoured EVH (OR 0.6; P = 0.003 and 0.002). Further, the number of bypass grafts was significantly increased in the endoscopic group, but these patients required less periprocedural blood transfusions (1.4 ± 1.8 vs 1.8 ± 3.0; P = 0.035). Minor wound healing complications were more common in the open group (10.3 vs 3.8%; P = 0.001). Severe complications in the leg requiring surgical revision occured in 2.4% of open vein harvested patients compared with 1.1% for endoscopic patients (P = ns). After a multivariate regression analysis, only female gender remained as a significant risk factor for impaired wound healing (OR 2.4; P = 0.001), whereas EVH reduced the risk of wound-healing complications (OR 0.4; P = 0.008).

CONCLUSIONS

EVH dramatically reduced postoperative would healing complications. Women were more likely to develop mild and severe leg wound complications. Therefore, women may benefit even more from EVH. In general, the favourable outcomes of EVH should result in a more widespread use of this technology in men and women.

Optimal timing of coronary artery bypass grafting in acute myocardial infarction

The timing of surgical coronary artery revascularization after an acute myocardial infarction is not well defined. The inherent difficulties of mobilizing a surgical team at odd hours has led to the adoption of a percutaneous coronary intervention strategy when possible or a clot-busting drug regimen when percutaneous coronary intervention is not available. Despite the difficulties and risks of surgical revascularization, there are situations where it may be indicated. We conducted a review of the literature to better understand the timing, scope, and risks of surgical coronary revascularization after an acute myocardial infarction.

Vascular tissue engineering by computer-aided laser micromachining

Many conventional technologies for fabricating tissue engineering scaffolds are not suitable for fabricating scaffolds with patient-specific attributes. For example, many conventional technologies for fabricating tissue engineering scaffolds do not provide control over overall scaffold geometry or over cell position within the scaffold. In this study, the use of computer-aided laser micromachining to create scaffolds for vascular tissue networks was investigated. Computer-aided laser micromachining was used to construct patterned surfaces in agarose or in silicon, which were used for differential adherence and growth of cells into vascular tissue networks. Concentric three-ring structures were fabricated on agarose hydrogel substrates, in which the inner ring contained human aortic endothelial cells, the middle ring contained HA587 human elastin and the outer ring contained human aortic vascular smooth muscle cells. Basement membrane matrix containing vascular endothelial growth factor and heparin was to promote proliferation of human aortic endothelial cells within the vascular tissue networks. Computer-aided laser micromachining provides a unique approach to fabricate small-diameter blood vessels for bypass surgery as well as other artificial tissues with complex geometries.

Myocardial infarction: a paradigm of success in modern medicine

Hospital mortality for acute myocardial infarction declined from 30% to 10% in the last 30 years, thanks to coronary care units and early revascularization with thrombolysis, angioplasty, and stent implantation. Pathologists played a major role by establishing plaque rupture and coronary thrombosis as the major cause of acute myocardial infarction and by discovering that ischemic myocardium necrosis progresses from endocardium to epicardium as a "wave front" phenomenon, with potential reversible injury if the reperfusion is accomplished within 3 h. Long-term mortality following myocardial infarction is mostly due to sudden electrical death, which may be prevented by pharmacologic (antiarrhythmic drugs) and nonpharmacologic (implantable cardioverter defibrillator, pacemaker) therapy. Ventricular assist devices may support the left ventricle as a bridge to transplantation. Long-term mortality at distance from acute myocardial infarction declined from 10% to 2% per year. Despite these indisputable achievements, there are still pending questions: in vivo identification of vulnerable plaque, mechanisms of thrombosis by plaque erosion, prompt treatment on the spot of instantaneous cardiac arrest by external defibrillation, adverse effect of myocardial reperfusion, fate of bare- and drug-eluting coronary stents. With these limitations and challenges well in mind, nowadays myocardial infarction does not represent a nightmare as it was in the past. The achievements in its prevention, diagnosis, and treatment should be considered as a pride of cardiovascular medicine.

[Rene Favaloro--a surgeon who has changed the history of coronary disease]

Rene Favaloro was one of the most distinguished surgeons of the 20th century. He was the first to introduce the original technique of aortocoronary bypass grafting, entering the new era of coronary artery disease treatment. Working at the Cleveland Clinic, together with Mason Sones and Effler, he became a member of the medical team which performered the first aortocoronary bypass grafting and showed the functional competence of the new graft. Although today percutaneous coronary interventions and coronary artery stents have a very important role in coronary artery disease treatment, five years after his death aortocoronary bypass grafting is the method of choice in selected groups of patients. Nowadays, when urgent percutaneous coronary interventions are an important treatment option in our country, it is good to remember that this also was the idea of Rene Favaloro and Mason Sones, who discussed agressive treatment in the first hours of myocardial infarction, and to remember his tremendous contributions and life dedicated to cardiosurgery.

Coronary artery bypass without cardiopulmonary bypass for patients with acute myocardial infarction

OBJECTIVE

Between January 1992 and December 1994, 57 patients having an acute myocardial infarction with coronary anatomy suitable for coronary artery bypass grafting without cardiopulmonary bypass underwent this procedure within 1 week of the infarction. We describe the surgical results of these high-risk patients.

METHODS

The study population included 43 male patients (75%) and 14 female patients (25%) whose mean age was 58.5 +/- 10.4 years. Thirty-two patients (56%) underwent emergency bypass grafting within 48 hours of an acute myocardial infarction, 4 of them (12.5%) as a bailout procedure after complicated percutaneous transluminal coronary angioplasty. Of these 32 patients, 7 patients (22%) were in cardiogenic shock, and 10 patients (31%) required preoperative intra-aortic balloon pump. Twenty-five patients (44%) underwent coronary bypass grafting 2 to 7 days after an acute myocardial infarction. The mean number of grafts per patient was 1.8 (range, 1-4), and the internal thoracic artery was used in 47 patients (82%). Only 7 patients (12%) received grafts to a circumflex marginal branch.

RESULTS

Operative mortality was 1.7% (1 patient), and the mean postoperative hospital stay was 6.8 +/- 3 days. One- and 5-year actuarial survivals were 94.7% and 82.3%, respectively. Angina returned in 7 patients (12%), 1 of whom underwent reoperation. Multivariate analysis revealed renal failure and preoperative cardiogenic shock to be independent predictors of overall mortality. Old myocardial infarction and operation within the first 48 hours were independent predictors of overall unfavorable outcome events.

CONCLUSIONS

These results suggest that coronary artery bypass grafting without cardiopulmonary bypass is a relatively low-risk procedure for patients having an infarction with coronary anatomy suitable for this technique.

VATS for complete dissection of LIMA in minimally invasive coronary artery bypass grafting

BACKGROUND

The aim of this work is to report our initial experience with minimally invasive coronary artery bypass grafting, using video-assisted thoracic surgery (VATS) to facilitate the operation and provide complete dissection of the left internal mammary artery (LIMA).

METHODS

Of 44 scheduled patients, 43 patients, 30 (69.8%) male, ranging in age from 31 to 83 years (60.8 +/- 12.0 years), with a severe lesion in the anterior descending artery, were operated upon. An 8-cm left anterior minithoracotomy was performed at the fourth intercostal space. Through this incision the optical device for video-assisted thoracic surgery as well as the surgical instruments were placed to provide complete LIMA dissection. This permits dissection until the subclavian region, allowing for anastomosis without tension or distortion. Bypass circulation was not used, and the cardiac rate was decreased with the use of intravenous beta-blockers. For LIMA-to-anterior descending artery anastomosis, proximal and distal tourniquets were used and 1.5 mg/kg of heparin was administered intravenously.

RESULTS

Video-assisted thoracic surgery provided a complete dissection of LIMA. The 43 patients presented satisfactory postoperative progress, being released from the hospital between 2 and 12 days after their operation, with a mean of 4 days. The patients have remained asymptomatic during a period that ranged from 1 to 13 months (6.3 +/- 3.5 months). During the follow-up, there was one death as a result of stroke and pneumonia 2 months after the release from the hospital.

CONCLUSIONS

The use of video-assisted thoracic surgery through thoracotomy allows the LIMA dissection without the necessity of other incisions. The procedure also permitted more ample dissection of LIMA when compared with minithoracotomy without video-assisted thoracic surgery.

Salvage angioplasty: an alternative to high risk surgery for unstable angina?

This prospective, Human Subjects Committee and Ethics Committee approved investigation was performed to determine if coronary angioplasty (PTCA) might be a reasonable alternative revascularization method for unstable angina patients thought to be at high risk for operative (CABG) mortality. Between March 1990 and October 1991, thirty-four consecutive patients with medically refractory rest angina were deamed to have high risk of surgical mortality and underwent PTCA without surgical backup. Predicted operative mortality was calculated for each patient based upon the VA Surgical Risk Assessment model. Angioplasty of 52 vessels was attempted. Reduction in lumenal narrowing to < 50% and improved angiographic flow was obtained in 47 vessels. There were four complicating infarctions. One death occurred in the lab, and three patients with unsuccessful angioplasty died within 30 days of pump failure. Relief of angina occurred in 30/34. Thirty patients were discharged home. In follow-up from 1 to 12 months, there have been 2 late sudden deaths at 4 months and 9 months, 1 death from lung cancer; 4 patients have stable exertional angina; 2 are awaiting heart transplant but are pain free, and one patient who had PTCA during cardiogenic shock from acute myocardial infarction had elective coronary artery bypass surgery. There have been no late myocardial infarctions. The observed angioplasty 30-day mortality of 11.8% (95% confidence limit 1% to 22.6%) compares favorably with the predicted operative mortality of 23.8% for this group. This prospective but non-randomized series supports the concept that balloon angioplasty may be a reasonable alternative to surgical intervention in some patients with unstable angina and high risk for surgery. A prospective randomized trial is warranted.

Unstable angina

Unstable angina can manifest as an array of symptom complexes. In some patients, medical therapy will stabilize the episodes of angina, and only predismissal exercise testing or angiography (or both) will be necessary. At the other end of the spectrum are patients with rest angina or multiple episodes of silent ischemia who are refractory to medical therapy and experience undetected microinfarction. Most of these patients require immediate catheterization and subsequent intervention with intra-aortic balloon pulsation, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting. An entire spectrum of manifestations exists between these two extremes. One challenge during the 1990s will be better stratification of patients with unstable angina so that safe, efficient, cost-effective treatment strategies can be appropriately applied to all patients.

Coronary angioplasty for early postinfarction unstable angina

Coronary angioplasty was performed in 53 patients in whom unstable angina had reoccurred after 48 hr and within 30 days after sustained myocardial infarction. Single-vessel disease was present in 64% of the patients and multivessel disease in 36%. The preceding myocardial infarction had been small to moderate in size in the majority of the patients. The left ventricular ejection fraction was more than 50% in 80% of the patients. Forty-five patients were refractory to pharmacologic treatment; eight were initially stabilized but once again became symptomatic with light exertion. Angioplasty was performed in 35 patients 2 to 14 days and in 18 patients 15 to 30 days after infarction (average 12 +/- 7 days after infarction). The initial success rate was 89% (47/53). The success rate of the patients treated at 2 to 14 days was lower (29/35, 83%) than that of patients treated at 14 to 30 days (18/18, 100%) but did not reach statistical significance (p less than .06). There were no deaths related to the procedure. In four of the six failures, emergency bypass surgery was performed and two patients sustained a myocardial infarction. Furthermore, a myocardial infarction complicated the angioplasty procedure in two other patients; thus the overall procedure-related myocardial infarction rate was 8% (4/53). At 6 months follow-up 26% (14/53) of all the patients who underwent angioplasty had recurrence of angina, which was successfully treated with repeat angioplasty, bypass surgery, or medical therapy. There were no late deaths. Late myocardial infarction occurred in two patients. Thus the total myocardial infarction rate after angioplasty at 6 months was 11% (6/53 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of collateral circulation on peri-infarct zone: assessment with stress thallium-201 scintigraphy

To evaluate the significance of collateral circulation on peri-infarct zone, stress myocardial scintigraphy and contrast left ventriculography (LVG) were performed in 38 patients with recent myocardial infarction (MI). All patients had at least one completely occluded coronary artery corresponding to the infarct area. In patients with good collaterals, stress induced transient enlargement of the perfusion defect, however, in those with poor or no collaterals the enlargement did not occur (p less than 0.05). Wall motion abnormality on LVG was significantly milder in the former patients than in the latter (p less than 0.001). Transient enlargement of the perfusion defect after stress and milder left ventricular asynergy were more frequently observed in patients with anterior MI and good collaterals. These observations indicate that good collaterals may keep some myocardium in the peri-infarct zone viable.

Early myocardial revascularization for postinfarction angina: results and long-term follow-up

Within 30 days of acute myocardial infarction, 108 consecutive patients underwent urgent surgical myocardial revascularization for postinfarction angina between July 1976 and March 1983. There were 84 men and 24 women whose mean age was 59.6 +/- 9.5 years (range 34 to 80). Group I (15 patients, 14%) underwent surgery within 48 hours, Group II (47 patients, 43%) between 3 and 7 days and Group III (46 patients, 43%) within 30 days. Fifty-nine patients (55%) had transmural infarction. The ejection fraction was less than 40% in 21 patients (19%). Left ventricular end-diastolic pressure was 20 mm Hg or greater in 42 patients (39%). The incidence of single, double, triple vessel and 70% or greater left main coronary artery stenosis was 4, 20, 59 and 17%, respectively. There were two deaths (1.8%) within 30 days of operation. The incidence of intraaortic balloon pumping was higher in patients operated on earlier after myocardial infarction (53% of Group I versus 22% of Group III). Statistically, there were no differences in the use of inotropic agents or the occurrence of arrhythmias or postoperative myocardial infarction in the three groups. Late follow-up (mean 35 months, range 18 to 98) is complete for all patients (100%). There were four late myocardial infarctions and eight deaths. Actuarial survival was 87% at 5 years. Seventy-three percent of the 108 patients were free of angina and the condition of 14% improved. These results indicate that myocardial revascularization in the first 30 days after myocardial infarction can be accomplished with morbidity and mortality rates similar to those of an elective operation for chronic angina refractory to medical management.

Predictors of outcome in early revascularization after acute myocardial infarction

We have reviewed 44 consecutive patients undergoing myocardial revascularization from 1 to 42 days after myocardial infarction. Operation within 12 days of transmural myocardial infarction carried a substantially high risk, particularly in patients with poor ventricular function. Patients with subendocardial infarction may be safely operated on shortly after infarction has occurred. In those with transmural infarcts, it may be advantageous to delay operation if early and aggressive medical therapy can effectively control the symptoms. This has to be counterbalanced, however, by the realization that the situation should not be allowed to slide into one of irreparable ventricular damage from infarct extension.

Increased regional end-diastolic wall thickness early after reperfusion: a sign of irreversibly damaged myocardium

Two-dimensional echocardiographic measurements of regional left ventricular end-diastolic wall thickness and systolic wall thickening were studied during coronary artery occlusion and early after reperfusion and compared with measurements of regional myocardial infarct size. In 25 closed chest anesthetized dogs with left anterior descending coronary artery occlusion followed by reperfusion, the occlusion period was 3 minutes in group I (n = 4), 20 minutes in group II (n = 4), 60 minutes in group III (n = 5) and 180 minutes in group IV (n = 12). Infarct size in groups III and IV was quantitated using the triphenyltetrazolium chloride technique. After coronary occlusion, wall thickening was replaced by thinning in the center of the ischemic region at the midpapillary echographic short-axis section, and no improvement in function occurred up to 60 minutes after reperfusion, except in group I. Ischemic zone end-diastolic wall thickness did not change significantly from control to the end of the coronary occlusion period, except Group IV. At 60 minutes after reperfusion, end-diastolic wall thickness increased only slightly in groups I and II (by 7.2 and 0.24%, respectively), but a marked increase was observed in groups III and IV (by 41 and 50%, respectively). The percent change in ischemic zone end-diastolic wall thickness from before reperfusion to 60 minutes after reperfusion correlated well with the amount of myocardial necrosis in corresponding segments (r = 0.936, standard error of estimate = 11.4%); an increase in segmental end-diastolic wall thickness of more than 25% was generally associated with 20% or more segmental necrosis. It is concluded that significantly increased regional end-diastolic wall thickness early after reperfusion is associated with irreversibly damaged myocardium, and this might be used as an index of myocardial salvage.

Postinfarction angina: results of early revascularization

To assess the efficacy of surgical revascularization for postinfarction angina within 30 days of acute infarction, the clinical course of 103 patients treated surgically from January 1979 to July 1982 was reviewed. There were 84 men (82%) and 19 women (18%) with a mean age of 58 years (range 34 to 80). Group A (11 patients) underwent surgery within 24 hours of infarction, Group B (21 patients) within 7 days and Group C (71 patients) within 30 days. Eighty-four patients (82%) had subendocardial infarctions and 19 patients (18%) had transmural infarction. Transmural infarction was more common in patients in Group A (36%) than in those in either Group B (19%) or Group C (15%). There were two deaths, both in Group C (1.9%), within 30 days of surgery. The use of intraaortic balloon or inotropic support and the occurrence of major arrhythmias or perioperative infarction was noted in 30 patients (29%) (64% in Group A, 33% in Group B and 18% in Group C). The average time in the intensive care unit was 3.2 days, with an average total hospital stay after surgery of 8.3 days. Late follow-up (mean 15.4 months, range 1 to 39) is complete for 97 patients (97%). There were no late myocardial infarctions and 93 patients (96%) were essentially free of angina. The only late death (1.0%) was caused by septicemia from delayed sternal wound infection. This study suggests that myocardial revascularization within the first 30 days after myocardial infarction can be accomplished with an acceptable operative mortality in selected patients with postinfarction angina refractory to medical management.

Coronary embolism: surgical management

The successful use of Fogarty catheter embolectomy combined with aortocoronary vein bypass graft in 4 patients with an acute myocardial infarction is presented. Three patients sustained acute occlusion of the coronary artery secondary to an embolus during cardiac catheterization. In the fourth patient, the left anterior descending coronary artery was occluded with a fragment of calcium debris during aortic valve replacement. All patients survived the operation. Acute occlusion of the coronary artery secondary to an embolus is uncommon, but its early recognition and appropriate surgical management may be lifesaving.