Emergency Coronary Artery Bypass Surgery Research Articles

Technology in interventional cardiology: Percutaneous transluminal coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) is now capable of providing myocardial revascularization in a majority of patients, but significant problems with the technique remain. It is unsuitable for dealing with diffuse coronary artery disease, chronically occluded vessels may be impossible to disobliterate, and disease of the distal coronary vessel may be difficult to reach with a balloon. Approximately 5 percent of all procedures may be complicated by acute occlusion of the target vessel, usually by dissection of the arterial intima, often resulting in a need for emergency coronary artery bypass surgery (CABG). Furthermore, there is recurrence of the dilated lesion--'restenosis'--in approximately 30 percent of cases in the first 3 to 6 months after PTCA. Advances in this technique, since its introduction in the mid 1970s, have been directed at making initial success more likely, obviating the need for emergency CABG, and reducing the incidence of restenosis.

True emergency coronary artery bypass surgery

Previous reports of emergency coronary artery bypass grafting often included cues that were not true surgical emergencies, thereby creating inappropriately favorable results. To accurately investigate this important subgroup of patients, we analyzed our recent experience with truly emergent coronary artery bypass grafting. From January 1984 to January 1989, 117 patients underwent true emergency bypass grafting for acute refractory coronary artery ischemia. Clinical deterioration was associated with failure of percutaneous angioplasty in 37 patients and instability during diagnostic catheterization in 13 patients. Refractory ischemia developed in the remaining patients while on the ward or in the intensive care unit. All operations were performed within four hours of surgical consultation, most within one hour. Overall in-hospital operative mortality was 14.5% ( 17 / 117 ), and 76.5% of deaths ( 13 / 17 ) were due to cardiac-related causes. Major morbidity occurred in 35.9% ( 42 / 117 ). Univariate analysis isolated ejection fraction, extent of coronary artery disease, previous myocardial infarction, hypertension, need for inotropic support, use of an intraaortic balloon pump, and cardiopulmonary resuscitation as risk factors for operative mortality. Stepwise multivariate analysis confirmed that previous myocardial infarction, hypertension, cardiopulmonary resuscitation, and reoperation were independently significant risk factors. Age, sex, diabetes, left main disease, and peripheral vascular disease had no significant impact on the prognosis. The 4% operative mortality ( 2 / 50 ) for patients taken directly to the operating room from the catheterization suite was significantly lower than the 22.4% mortaiity ( 15 / 67 ) associated with emergerncies arising on the ward or intensive care unit ( p < 0.01). A logistic risk equation developed from this population accurately modeled operative mortality. All 9 patients predicted to have a greater than 90% risk of operative death died, whereas only 1 (1.5%) of the 65 patients predicted to have a less than 5% risk died. We conclude that true emergency coronary artery bypass grafting carries a particularly high risk, with an operative mortality in the range of 15%. This finding merits full consideration when making therapeutic decisions concerning this group of critically ill patients.

Continuous rt-PA infusion as a salvage strategy to maintain patency off the infarct artery; safety of high cumulative dose and subsequent emergency coronary artery angioplasty and bypass surgery

Acute re-occlusion of an infarct artery reperfusion attained by thrombolytic therapy may be treated by emergency coronary angioplasty or bypass surgery. Repeated infusion of a thrombolytic agent is an additional treatment strategy. Three patients with reinfarctions that occurred very early after successful reperfusion were treated with continuous infusion of recombinant tissue-type plasminogen activator (rt-PA). These patients received a rt-PA dose of 300-360 mg while they awaited emergency mechanical revascularization procedures. Two patients had coronary angioplasty immediately after receiving repeated infusions of rt-PA and one underwent coronary bypass surgery while receiving a third rt-PA infusion. There were no bleeding complications in the 2 patients who underwent coronary angioplasty, and no excessive bleeding in the patient who received coronary bypass surgery. Thus, repeated continuous rt-PA infusions can be used to maintain the patency of recurrently occluding infarct arteries until definitive mechanical revascularization can be performed.

Role of intracoronary thrombus in acute complications during percutaneous transluminal coronary angioplasty

Coronary angiograms from 2,372 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were retrospectively reviewed for the presence of intracoronary thrombus (ICT) before dilatation. Patients with evolving acute myocardial infarction and those receiving thrombolytic therapy were excluded from analysis. Coronary artery thrombus was present in 126 patients (6%) (group 1). When compared to 2,246 patients (group 2) without ICT, group 1 had a higher incidence of unstable angina, 74% vs. 66% (less than 0.06), previous myocardial infarction, 59% vs. 37% (P less than .0001), and history of a recent myocardial infarction, 28% vs. 9% (P less than .0001). Patients with predilatation intracoronary thrombus had a higher risk for acute occlusion, 6% vs. 2% (P less than .002); however, the incidence of emergency coronary bypass surgery and myocardial infarction was similar in both groups. Therefore, the presence of predilatation intracoronary thrombus heralds an increased risk of acute occlusion, but not myocardial infarction or emergency coronary artery bypass surgery.

Value of the ST-T segment in lead V4R in inferior wall acute myocardial infarction to predict the site of coronary arterial occlusion

The treatment of acute myocardial infarction (AMI) has changed dramatically with the introduction of thrombolytic therapy, immediate angioplasty and emergency coronary artery bypass surgery. Several studies1e3 have shown that the success rate of these procedures depends on the time interval between the onset of complaints and the achievement of reperfusion. In patients admitted with an inferior wall AMI, the coronary artery causing the AM1 can be the right or the left circumflex artery. Our previous investigations, as well as those of others,4-6 have shown that the recording of lead V4R in the acute phase of an inferior wall AM1 can distinguish those patients with a proximal occlusion of the right coronary artery from those with an occlusion of the distal right or left circumflex artery, the first group of patients showing ST-T-segment elevation I1 mm in lead V4R. However, it is not possible to differentiate between occlusion of a distal right coronary artery and a circumflex artery using this criterion. In these patients (possible candidates for intracoronary thrombolytic therapy), coronary arteriography might start with the “wrong” coronary artery leading to a delay in reperfusion. Retrospectively, we have analyzed the configuration of the ST-T segment in lead V4R to determine if changes in the ST-T segment can help predict the site of coronary occlusion in inferior wall AMI.

Restenosis after successful coronary angioplasty. Pathophysiology and prevention.

OVER the past decade, percutaneous transluminal coronary angioplasty has gained wide acceptance as the procedure of choice in many patients with atherosclerotic coronary artery disease. As experience with the procedure has grown, its rate of success has risen to approximately 90 percent and the incidence of acute complications has fallen; as a result, emergency coronary-artery bypass surgery is required in less than 4 percent of patients.1 2 3 Despite these improvements, re-Stenosis in the days, weeks, or months after successful angioplasty of a narrowed coronary artery occurs in 25 to 35 percent of patients,3 4 5 6 7 or 45 to 55 percent of those with . . .

Emergency coronary artery bypass surgery preserves global and regional left ventricular function after intravenous tissue plasminogeh activator therapy for acute myocardial infarction

Emergency coronary bypass surgery was performed in 24 (6.2%) of 386 consecutive patients enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Multicenter Trial. Intravenous tissue plasminogen activator was administered 2.6 ± 0.7 h and bypass surgery was performed 7.3 ± 1.9 h after the onset of infarction. Infarct artery patency was achieved in 21 (88%) of the 24 patients (pharmacologically in 18 or mechanically with coronary angioplasty in 3) in the catheterization laboratory before bypass surgery.The indication for surgery was left main or equivalent coronary artery disease in 7 patients, coronary anatomy unsuitable for angioplasty in 4 patients and unsuccessful coronary angioplasty in 13 patients. A coronary perfusion catheter was inserted before surgery in 11 of 13 patients with unsuccessful angioplasty. All three deaths occurred postoperatively in patients with preoperative cardiogenic shock. Three patients required surgical reexploration for postoperative hemorrhage. Comparison of preoperative and predischarge contrast left ventriculograms demonstrated significant preservation of global (left ventricular ejection fraction 49 ± 6 to 56 ± 6%; p = 0.008) and regional (standard deviation/chord −2.6 ± 0.5 to −1.5 ± 1.1: p = 0.001) left ventricular function.Emergency coronary bypass surgery tan he performed with a low morbidity and mortality in patients treated with intravenous tissue plasminogen activator therapy for acute myocardial infarction. Such therapy is associated with significant preservation of global and regional (infarct zene) left ventricular function.

Acute complications of elective coronary angioplasty: a review of 500 consecutive procedures.

In 500 consecutive procedures of elective coronary angioplasty attempted at a centre with a primary success of 86%, one or more major acute complications occurred in 34 cases (6.8%). Twenty four patients (4.8%) sustained an acute myocardial infarction (in six this was despite emergency coronary artery bypass surgery) and two patients (0.4%) had emergency coronary bypass without myocardial infarction. Ventricular fibrillation was a complication without sequelae in five (1.0%) patients; one (0.2%) patient died because of refractory ventricular fibrillation and ensuing electromechanical dissociation. "Benign" coronary artery rupture occurred in one (0.2%) patient, and one (0.2%) patient had elective coronary surgery to retrieve the tip of a fractured guide wire after an otherwise successful angioplasty. Despite a low mortality, coronary angioplasty is associated with major complications in about one of 14 procedures; the complication is usually acute myocardial infarction caused by occlusion of the vessel.

Angiographic follow-up after multivessel percutaneous transluminal coronary angioplasty

In 100 consecutive patients undergoing multivessel percutaneous transluminal coronary angioplasty (PTCA), dilation was attempted in 207 arteries. Primary success was achieved in 85 patients. Complications occurred in 8 patients: acute myocardial infarction in 5 and need for emergency coronary artery bypass surgery in 5. Control angiography was done in 77 of 85 patients (91%) with primary success at a mean of 12 ± 6 months. Complete revascularization had been achieved in 59 patients and incomplete revascularization in 18. Angiographic restenosis was found in 39 of 77 patients (51%) and in 47 of 143 arteries (33%) at 9 ± 7 months. The restenosis rate was 57% for chronic total occlusions (8 of 14) and 30% for stenoses (39 of 129). The restenosis rate was significantly higher for the left anterior descending coronary artery (40%) than for the left circumflex coronary artery (21%). However, the significance was lost after exclusion of chronic total occlusions. A higher residual stenosis and a high coronary wedge pressure were predictors for restenosis. Restenosis was clinically silent in 14 patients (18%). Repeat PTCA was done in 19 patients with recurrence and elective surgery in 8. Clinical follow-up was available in all patients at 24 ± 12 months. Patients with incomplete revascularization had less favorable clinical follow-up results than patients with complete revascularization: 44% (8 of 18) vs 81% (48 of 59) were asymptomatic (p < 0.005), and 28% (5 of 18) vs 5% (3 of 59) had undergone elective bypass surgery during follow-up (p < 0.005). Most patients with restenosis after multivessel PTCA had only 1-vessel restenosis and only 7% had restenosis of all lesions.

High risk percutaneous transluminal coronary angioplasty in the treatment of severe coronary artery disease

We report on 27 “high risk” patients out of 171 consecutive patients undergoing percutaneous transluminal coronary angioplasty from June 1984 to August 1985. The ages ranged from 31–80 years (mean 62.7 ± 10) years. High risk percutaneous transluminal coronary angioplasty was defined as: (1) salvage cases (3 patients) where the patients presented in cardiogenic shock or the vessels were not bypassable; (2) multivessel coronary artery disease (22 patients) where a large area of jeopardized myocardium was dependent on the angioplasty vessel(s); (3) left ventricular dysfunction (7 patients) as defined by two of the three criteria: (a) left ventricular end-diastolic volume index > 100 ml/m 2; (b) ejection fraction < 30%; and (c) left ventricular end-diastolic pressure > 20 mm Hg. The initial success rate in the high risk patients was 85.2%. Emergency coronary artery bypass surgery in these patients was 7.4%. There was one death in the high risk group, as one of the salvage cases died 24 hours after successful percutaneous transluminal coronary angioplasty due to severe underlying myocardial disease. In conclusion percutaneous transluminal coronary angioplasty can be successfully performed in high risk patients with a low complication rate and should be considered as an alternative to coronary artery bypass graft surgery in selected high risk patients.

Coronary angioplasty of the unstable angina related vessel in patients with multivessel disease.

This study is a retrospective analysis of the efficacy of percutaneous transluminal coronary angioplasty of the ischaemia-related vessel in patients with unstable angina. Forty-three patients had multivessel disease with dilatation of the ischaemia-related vessel only (group I; partial revascularization) while 111 patients had single vessel disease only (group II; total revascularization). The initial success rate in both groups was identical (88 versus 88%). The need for emergency coronary artery bypass surgery was similar in the two groups (group I 12% versus group II 9%; NS). The total post PTCA myocardial infarction rate (despite urgent CABG) was also similar in the two groups (group I 9% versus group II 10%; NS). The results of electrocardiographic exercise testing and Thallium-201 scintigraphy provide objective evidence for incomplete revascularization in group I. The maximum workload achieved was lower, and the frequency of exercise induced angina, ST-segment depression and reversible perfusion defect was higher than in group II. Moreover, at 6 months follow-up the recurrence rate of angina pectoris rate was higher in group I than in group II (29% versus 16% P less than 0.05). It is concluded that dilatation of the ischaemia related vessel only in patients with unstable angina and multivessel disease is as effective in the management of the acute phase of unstable angina as is dilatation of the ischaemia related vessel in patients with single vessel disease. However, due to only partial revascularization the recurrence rate of angina pectoris is higher.

Safety and success of the beginning percutaneous transluminal coronary angioplasty program using the steerable guidewire system

To determine the safety and success rate of a beginning percutaneous transluminal coronary angioplasty (PTCA) program using the steerable guidewire system, results of the initial 100 attempted dilatations were analyzed. In accordance with recommended guidelines, the operators had extensive experience in cardiac catheterization and attended demonstration courses in PTCA to learn the technique, but had no in-laboratory training or assistance from experienced PTCA operators. Using the same criteria for success and complications, the results with the steerable guidewire system were compared with those of the National Heart, Lung, and Blood Institute Registry of programs beginning coronary angioplasty with the nonsteerable, fixed guidewire system. Success rates were 95% and 59%, emergency coronary artery bypass surgery 1% and 6%, acute coronary occlusion 1% and 5%, and myocardial infarction 3% and 5%. The success and complication rates were similar for each decile in the 100 procedures, in contrast to the Registry in which results significantly improved as operator experience increased. The average stenosis was reduced from 86 to 28% and the average gradient was reduced from 51 mm Hg to 14 mm Hg. These results indicate that cardiologists experienced in cardiac catheterization can start a PTCA program using the steerable guidewire system and have an improved learning curve compared with previously reported experience in which the nonsteerable, fixed guidewire system was used. With careful case selection, results comparable to those of experienced PTCA operators can be achieved. These findings may provide a more accurate prediction of the results that can be expected in a beginning PTCA program using current techniques and equipment.

Results of percutaneous transluminal coronary angioplasty by multiple relatively low frequency operators

Results of percutaneous transluminal coronary angioplasty (PTCA) were analyzed from July 1983 through April 1985. Sixteen physicians performed 131 PTCAs from July 1983 through June 1984 (1983/84) (mean 0.7 PTCAs per physician per month) and 279 from July 1984 through April 1985 (1984/85) (mean 1.7 PTCAs per physician per month). Success rates rose from 76% in 1983/84 to 84% in 1984/85 (difference not significant [NS]). The incidence of emergency coronary artery bypass surgery fell from 11% in 1983/84 to 5.4% in 1984/85 (p < 0.05). Results for 1984/85 were separated into 2 groups according to the mean number of PTCAs per month performed by each physician. Success rates for group I (2 or fewer PTCAs per month) and group II (more than 2 PTCAs per month) were 83% and 84% (NS) for all PTCAs attempted and 89% and 88% (NS) for PTCAs excluding those attempted during acute myocardial infarction or on totally occluded vessels. The similar results of both groups may reflect the performance of the catheterization laboratory PTCA team and the assistance of more experienced physicians, in addition to the performance of each individual physician. These findings must be applied with caution to laboratories with different organization and with less frequent PTCA experience.

Transluminal coronary angioplasty in the elderly

The safety and clinical efficacy of percutaneous transluminal coronary angioplasty (PTCA) in elderly patients has not been established. Of 639 PTCAs performed between March 1980 and May 1984, 119 patients were 65 years or older (mean 70 years). On angiography, elderly patients differed only in the more frequent occurrence of visible calcific deposits (26% vs 8 % in younger patients, p < 0.01). Primary success was achieved In 81%, vs 80% in patients younger than 65 years. Major complication rates were comparable to those of younger patients: emergency coronary artery bypass surgery, 4.1% vs 4.7% ; acute myocardial infarction, 2.5% vs 2.9%; and death, 0.8% vs 0. Late clinical follow-up ranging from 5 to 50 months (mean 18) showed that symptomatic improvement was achieved in 91 % of patients in whom PTCA was successful, with 55% being asymptomatic. Seventy percent of patients were as active or more active (30%) than before PTCA and 47% were taking fewer medications. Four late deaths occurred, none from cardiac causes. These data support the safety and clinical effectiveness of PTCA in elderly patients and justify the extension of indications for PTCA to selected patients with multivessel disease in this age group.

Emergency coronary artery bypass surgery after intracoronary thrombolysis for evolving myocardial infarction.

Sixteen patients underwent emergency coronary artery bypass surgery immediately after intracoronary streptokinase infusion for acute evolving myocardial infarction. Of these, 11 patients had 70% residual stenosis in the recanalised vessel, and in five thrombolysis was unsuccessful. There were no hospital deaths. All the patients sustained myocardial necrosis, the peak activity of creatine phosphokinase correlating with the time to reperfusion. Chest tube drainage (mean 960 ml) was significantly higher than for control patients but did not correlate with the total dosage of streptokinase. No patients had further myocardial infarction or developed recurrent angina. Selected patients may benefit from coronary bypass surgery after intracoronary streptokinase infusion. If necessary this may be performed immediately with low mortality and morbidity.

Experience of emergency coronary artery bypass grafting surgery and operative transluminal coronary angioplasty.

Our experience of performing emergency coronary artery bypass surgery in 9 patients with acute myocardial infarction (AMI) and of intraoperative transluminal coronary angioplasty (OTCA) during bypass surgery in another 28 patients was reviewed. Data were evaluated in conjunction with the recent application of intracoronary thrombolytic therapy and percutaneous transluminal coronary angioplasty. In 4 of the 9 cases where the emergency coronary artery bypass grafting (CABG) was performed within 2 hours after the onset of AMI, no new Q waves appeared in electrocardiograms (3 cases), and remarkable improvement of left ventriculographic findings was noted when pre- and postoperative ventriculograms were compared in 2 of these 4 cases. Intraoperative transluminal coronary angioplasty was successful in only 51.6% of the cases when evaluated at the post bypass period and this was less successful than our experience with PTCA. The low success rate was considered to be due to the greater amount of intimal fibrosis in the more distal portion, where the OTCA is performed, than is found in the proximal portion of the coronary arteries.

Percutaneous Transluminal Coronary Angioplasty

Percutaneous transluminal coronary angioplasty appears to be an effective alternative to coronary artery bypass surgery in patients whose coronary artery anatomy is suitable--that is, an individual with single (or, at most, double) vessel coronary artery disease whose stenoses are proximal, discrete, subtotal, concentric and noncalcified. Since emergent coronary artery bypass surgery is required in 5% to 7% of patients even when angioplasty is attempted by an experienced physician, the patient should be an acceptable candidate for surgery from both a cardiac and noncardiac standpoint. Unfortunately, ideal angioplasty candidates are a distinct minority among those with coronary artery disease. If the procedure is reserved for ideal (or nearly ideal) candidates, the rate of success should approach 75% to 80%, and the incidence of major complications should be below 10%. Although the procedure appears to be effective in alleviating angina, it is unlikely that it will exert a beneficial effect on survival when compared to either medical therapy or coronary artery bypass surgery.

Effect of whole-body hypothermia on myocardial blood flow and infarct salvage during coronary artery occlusion in dogs

The effect of moderate whole-body hypothermia on blood flow to acutely ischemic and nonischemic myocardium and on the relationship between blood flow and necrosis after 5 hours of left anterior descending (LAD) coronary artery occlusion was investigated in 20 dogs. Blood flow to ischemic myocardium was not significantly increased or decreased by hypothermia. However, much less myocardial necrosis (shown by nitro blue tetrazolium staining) was observed in the hypothermia-treated animals. Therefore, this protective effect of hypothermia is not a result of improved blood flow to the ischemic region, but is more likely due to decreased metabolic requirements. Nearby noninfarcted myocardium had slightly higher blood flow than homologous tissue in the corresponding controls under both normothermic and hypothermic conditions. This tissue, which must compensate for the loss of contractility in the ischemic region, appears to maintain its ability to respond to increased demand for blood flow even during moderate hypothermia. Blood pressure and cardiac output data indicate that hypothermia did not interact with myocardial infarction to produce or exacerbate cardiogenic shock. Consequently, whole-body hypothermia may prove to be a safe and effective emergency pretreatment which may significantly decrease the amount of necrotic myocardium when initiated prior to emergency coronary artery bypass surgery.

Frequency and importance of unprovoked coronary spasm in patients with angina pectoris undergoing percutaneous transluminal coronary angioplasty

Coronary spasm superimposed on fixed coronary artery stenosis was discovered in 14 of 74 candidates for percutaneous transluminal coronary angioplasty (PTCA). In 3 of the 14, spasm developed during PTCA and was presumably catheter-induced. Eleven of the 14, with unprovoked spasm, are the subject of this study. Three of the 11, in whom the fixed component of the mixed stenosis was subcritical were treated medically, with good results in 2 but with persistent angina pectoris and eventual myocardial infarct in 1. Nitroglycerin administered by the intracoronary route relieved spasm resistant to sublingual nitroglycerin in 1 of the 3. In 8 of the 11 with critical fixed stenosis, spasm was discovered either before PTCA (7 patients) or on follow-up (1 patient). Six of the 8 had successful PTCA, with no or mild symptoms on follow-up. Of the 2 failures, 1, uncomplicated, was followed by successful elective coronary artery bypass surgery while the other, complicated, led to successful emergency coronary artery bypass surgery, with disappearance of symptoms in both. The rate of success was similar in patients with documented unprovoked spasm (6 of 8) and patients without (39 of 63, 62%). It is concluded that (1) coronary spasm, if properly sought for, is probably not uncommon in single-vessel candidates for PTCA; (2) patients considered candidates for PTCA should have intracoronary nitroglycerin administered before PTCA; (3) in patients with critical, fixed coronary artery disease, associated spasm does not reduce the chances of successful PTCA; (4) coronary spasm may outlast the relief by PTCA of the fixed component of the mixed stenosis and requires long-term vasodilator therapy; and (5) the lack of adverse effects when PTCA is performed in patients with spasm superimposed on critical fixed single-vessel stenosis appears to justify its use for the time being.

Transluminal coronary angioplasty of the right coronary artery brachial cutdown approach.

Transluminal coronary angioplasty (TCA) of the right coronary artery (RCA) was performed by brachial cut-down approach in 33 patients during a period of 16 months. Flexible-tip guiding catheters were used in all cases. TCA was successful in 27 of 33 patients (81%). The stenosis was reduced in successful cases from a mean of 89% predilatation to 26% postdilatation (P less than 0.001). The systolic pressure gradient across the lesion was reduced from a mean of 49 mm Hg to 4 mm Hg (P less than 0.001). Following successful TCA, patients experienced marked improvement in clinical status, functional capacity, and relief of angina. The complication rate in this study was low. There was no early or late mortality. The most common complication was dissection of the coronary artery occurring in four cases (12%). One patient sustained an acute inferior myocardial infarction. Only one patient required emergency coronary artery bypass surgery. The late follow-up (mean 6 months) angiography was obtained in 17 patients. The stenosis recurred in late follow-up in three cases (18%). Our initial experience revealed that the use of softer guiding catheters by brachial technique offers more selective approach for TCA of RCA lesions and provides better results than percutaneous femoral approach with fixed-tip catheters. Our success rate of 81% for dilatation of RCA is significantly higher than previously reported.