The morbidity and mortality of reoperation for coronary artery disease and analysis of late results with use of actuarial estimate of event-free interval

Protection of the internal mammary artery pedicle with polytetrafluoroethylene membrane

With increasing frequency, reoperative coronary artery bypass surgery is being performed in the setting of a patent internal mammary artery (IMA) graft. Injury to the IMA graft at reoperation can result in ischemic myocardial injury and cardiac arrest. This descriptive laboratory study examined use of a polytetrafluoroethylene (PTFE) membrane wrap to protect the IMA pedicle during sternal reentry. Six pigs (25-30 kg) underwent median sternotomy and takedown of left and right IMAs. Grafts were implanted in the epicardium by a modified Vineberg procedure. In each animal, one IMA was wrapped circumferentially with PTFE, while the contralateral bare IMA served as the control. Redo sternotomy was performed 3 months later. Severe adhesions between chest wall, myocardium, and bare IMA grafts were encountered in six of six animals. PTFE-wrapped IMAs were easily identified by appearance and by palpation. There was no adherence between PTFE membranes and surrounding tissue, nor was there evidence of cellular infiltration, disruption, or contraction of the membrane. Most notably, PTFE membranes could not be cut or injured with the electrocautery, since they are electrical nonconductors. This study demonstrates that PTFE membrane: (1) is relatively inert and incites minimal surrounding tissue reaction; and (2) is impenetrable to electrocautery injury. Further studies are necessary to determine the impact of PTFE membrane on IMA graft patency and wound infection. PTFE membrane may prove clinically useful in protecting patent IMA pedicles during reoperative cardiac surgery.

Balloon angioplasty for the treatment of lesions in saphenous vein bypass grafts

OBJECTIVES

The purpose of this review is to assess the value and limitations of balloon angioplasty for the treatment of saphenous vein bypass graft obstructions. The potential efficacy of new interventional techniques is discussed.

BACKGROUND

Treatment of ischemia due to saphenous vein bypass graft obstructions poses a difficult problem that will be encountered more often as the pool of surgically treated patients continues to accumulate. Reoperation is technically demanding and is associated with high mortality and morbidity rates. Balloon angioplasty may provide a suitable alternative.

METHODS

The review proposes a classification of patients with attempted saphenous vein graft angioplasty according to expected early and late outcome based on the data obtained from the relevant published data and personal experience.

RESULTS

Angioplasty of a nonocclusive obstruction in a saphenous vein bypass graft has an initial success rate of approximately 90% and is a safe procedure (procedural death rate < 1%, myocardial infarction rate < 4%). The overall average restenosis rate is 42%. Surgical standby is limited and technically difficult. Angioplasty of chronic total occlusions in old grafts is associated with poor initial and long-term results. The long-term clinical results are unfavorable because of the continuing progression of disease in nontreated vein graft segments and native coronary arteries, in addition to the high restenosis rate. New techniques, although promising, have shown neither better initial results nor reduction of restenosis. Stent placement may be useful in longer graft lesions containing friable material.

CONCLUSIONS

Patients may be classified into three groups according to expected early and late outcome on the basis of 1) unfavorable graft anatomy, 2) risk of cardiogenic shock in event of acute graft closure, and 3) age of grafts. The three groups are 1) those with an initial high success, low procedural risk and low restenosis rate; 2) those with an initial high success but high procedural risk and moderate to high restenosis rate; and 3) those with a low success, high risk and high restenosis rate. Balloon angioplasty to treat lesions in venous bypass grafts should be considered a palliative procedure, not a long-term solution, for ongoing progression of coronary artery and vein graft disease. The induced high restenosis rate remains a significant problem.

The Tracker catheter: a new vascular access system

Technologic advances in dilation equipment have been important in improving angioplasty success rates and in expanding the indications of dilation. Despite these improvements, approximately 7% to 10% of attempted dilations may ultimately fail because of inability to cross the culprit lesion. As angioplasty techniques are applied to an increasingly complex cohort of patients, the ultimate success of a given procedure depends more and more on the ability of the operator to select the appropriate equipment for a given procedure. We report the unique application of a commercially available perfusion catheter which may improve patient outcome during complex angioplasty.

Reoperation for recurrent coronary artery disease--a ten year experience

The need for reoperation caused by recurrence of coronary artery disease is becoming increasingly common. Although reoperation is more difficult and time-consuming, with careful surgical technique it can be carried out with the same mortality as that described by many units for primary coronary artery bypass grafting (1.2-2.0%). In the 172 patients described here, who had coronary artery reoperations between 1981 and 1990, there were two in-hospital deaths (1.2%). There were three postoperative bleeds which required return to theatre. No patient suffered a postoperative neurological deficit or postoperative myocardial infarction. These reoperations comprised 6.9% of the 2497 coronary artery operations carried out in the same period. Follow-up disclosed eight late deaths, from five-62 months after operation; all survivors claim to be symptomatically improved. Consideration should be given to the potential problems of reoperation when carrying out primary myocardial revascularisation.

Stenting of venous bypass grafts: a new treatment modality for patients who are poor candidates for reintervention

During a 2-year period, 136 self-expanding Wallstents were implanted in saphenous vein bypass grafts in 69 patients with end-stage coronary artery disease. All patients had severe symptoms and the majority were poor candidates for either repeat surgery or conventional bypass coronary angioplasty because of unfavorable native anatomy, impaired left ventricular function, or a high-risk bypass lesion anatomy for coronary angioplasty. All procedures were technically successful without major complications and a need for emergency bypass surgery. However, during the hospital stay acute thrombotic complications occurred in seven patients (10%) resulting in one death and acute myocardial infarction in five patients and necessitating emergency repeat PTCA in two patients and repeat CABG in four. Twenty-three patients had serious hemorrhagic complications directly related to the rigorous anticoagulation schedule. Two patients died of fatal cerebral bleeding. During follow-up, another five patients died accounting for a total mortality rate of 12%. At late angiographic follow-up (4.9 +/- 3.4 months, n = 53), 25 patients (47%) had a restenosis (greater than or equal to 50% DS) within or immediately adjacent to the stent, necessitating reintervention in 19 patients (PTCA, n = 12; repeat CABG, n = 7). In the group without stent-related restenosis (n = 28), 15 patients had progression of disease in either the native or bypass vessels leading to recurrence of major anginal symptoms within 1 to 24 months. Ten of these patients required further intervention (stent, n = 6; PTCA, n = 3; repeat CABG, n = 1). Stenting in saphenous coronary bypass grafts can be performed safely with excellent immediate angiographic and clinical results.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple reoperative coronary artery bypass grafting

Initial reoperative coronary artery bypass grafting is being performed commonly, and an increasing number of patients are being referred for subsequent reoperative coronary artery bypass grafting. From January 1980 through June 1990, 53 patients (52 male, 1 female) underwent a third or fourth coronary artery bypass operation and were retrospectively reviewed. This represented 0.3% (53/17,102) of the coronary artery bypass procedures done during that time period. The mean age was 59 +/- 8 years. The number of grafts placed ranged from one to four with an average of 2.6 per patient. Internal mammary artery grafts were used in 30 patients (57%). The mean left ventricular ejection fraction was 0.52 +/- 0.13. Intraaortic balloon pump support was necessary in 10 patients postoperatively. There were no intraoperative deaths, although 4 patients died in the postoperative hospitalization period. Perioperative myocardial infarctions were diagnosed in 6 patients, 13 patients had perioperative dysrhythmias, and 2 patients sustained a stroke. Superficial wound infections occurred in 5 patients. Late follow-up in 49 patients revealed that 2 other patients have since died, and no further myocardial infarctions have been reported in the survivors. Postoperative 3-year survival is 85%, whereas 3-year myocardial infarction-free survival is 70%. Although there is increased risk of operative complications and early death after multiple reoperative coronary artery bypass grafting, both in-hospital and long-term results suggest that it is an appropriate therapeutic strategy.

Anterior sternal retraction for reoperative median sternotomy

The incidence of reoperative median sternotomy for repeat cardiac surgery is increasing. Reoperative median sternotomy is associated with a higher morbidity and mortality than first-time cardiac surgery. A portion of this morbidity and mortality may be due to direct injury to the heart and great vessels in the process of reopening the sternum. We report a new technique utilizing anterior sternal retraction that allows division of adhesions between the undersurface of the sternum and the heart and great vessels under direct vision. This technique enables the surgeon to minimize the risk of serious injury to these underlying structures during reoperative cardiac surgery.

The acute and chronic effects of G-lasing on femoral vein grafts in dogs

Each year, 5% of all coronary artery bypass operations are repeat procedures, and 15%-30% of coronary artery vein grafts occlude within the first eighteen months postoperatively. To evaluate the macroscopic and histologic effects of G-lasing on vein grafts and their patency, femoral veins were used to bypass bilaterally induced stenoses of femoral arteries in 10 dogs. The left vein grafts were G-lased with a 1.5 mm, hot-tipped argon laser at 5 watts for ninety seconds, while the right grafts were used as the controls. Acutely, each vein graft demonstrated no evidence of charring or perforation. The percentage of endothelium present in the G-lased vein grafts was consistently less than 5%, whereas the control vein grafts had an average of 70%. After ten weeks, the animals were sacrificed, and the vein grafts were evaluated for histologic changes and patency. There were no significant microscopic differences between the G-lased and control vein grafts. A statistically significant difference in graft patency was not achieved between G-Lased and control vein grafts at 10 weeks, but only a small number of grafts were studied. Further studies will be needed to evaluate the effects of G-lasing on the long-term patency of vein grafts.

Late results of 200 repeat coronary artery bypass operations

To determine the clinical outcome and the long-term results of a second coronary artery bypass operation, we studied preoperative clinical status and catheterization data in 200 consecutive patients over a 9-year period (1979 to 1987) (mean follow up time 34 months, maximum 120). The study group included 169 men and 31 women (mean age 58.4 years [7% greater than 70 years]). Sixty-four percent of patients had severe angina (New York Heart Association class IV), 70% had 3-vessel coronary artery disease and 21% had poor left ventricular function. Reoperation was performed after a mean interval of 58 months after the first procedure. A mean of 3.3 distal anastomoses was placed. The operative mortality rate (30 days) was 7.5%, with additional cardiac morbidity (myocardial infarction, heart failure) in 11.5% of patients. Multivariate analysis showed an increased risk in women (risk ratio 3.6) and in patients with poor left ventricular function (risk ratio 3.1). The cumulative 5-year survival rate was estimated at 84%, with a rate of 77% for patients with poor left ventricular function (difference not significant). The probability of remaining free of a cardiac-related event (myocardial infarction, angioplasty, third operation, cardiac death) was 64% for 5 years. At the end of follow-up, 79% of the surviving patients were in New York Heart Association class I or II and nearly 50% of patients in the fifth year after the reoperation had good functional status. It is concluded that a reoperation is effective but carries an increased, immediate, operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial revascularization for the third time. Clinical characteristics and follow-up

Twenty-five patients presenting for a third revascularization procedure were retrospectively reviewed at Loyola University Medical Center, Maywood, IL. This represents 0.5 percent of the total revascularization cases over a five-year period extending from 1985 through 1989. Perioperative mortality was none, and seven complications occurred in six patients. Internal mammary arteries were used for revascularization in 60 percent of this group. Follow-up reveals that only one patient has died secondary to an arrhythmia. All patients except one are symptomatically improved, and 18 patients remain angina free at a mean follow-up of 22.3 months. It is therefore concluded that patients are clinically improved with a third revascularization, and this procedure should be offered as an effective means of treatment.

Early postoperative balloon coronary angioplasty for failed coronary artery bypass grafting

In a small number of patients, coronary artery bypass grafting (CABG) fails to relieve anginal symptoms. The usefulness of coronary angioplasty for the treatment of early (less than or equal to 90 days) recurrent ischemia after CABG was examined. Forty-five patients were treated from 2 to 90 days after CABG, including 8 patients studied emergently for prolonged ischemic symptoms. One-, 2- and 3-vessel native disease was found in 4, 10 and 31 patients, respectively. At the time of postoperative angiography, the major anatomic mechanism of recurrent ischemia was complete vein graft occlusion in 12 patients (27%), internal mammary artery occlusion in 3 (7%), vein graft stenoses in 13 (29%), internal mammary artery stenoses in 10 (22%), unbypassed disease in 4 (8%) and disease distal to the graft insertion site in 3 (7%). Angioplasty was successful at 91 of 98 sites (93%), including 95% of 41 lesions in native arteries, 89% of 46 lesions in vein grafts and 100% of 11 internal mammary artery lesions attempted. Complete revascularization was achieved in 84% of patients. There were 2 in-hospital deaths and 2 myocardial infarctions. Two additional patients underwent repeat CABG before discharge after uncomplicated but unsuccessful angioplasty. At late follow-up of the 43 survivors (mean 44 months), there were 4 deaths, 2 of which were noncardiac. Repeat CABG was required in only 3 patients and repeat angioplasty was performed in 10. Angina was absent or minimal in 35 patients; 17 patients were employed full time. Thus, percutaneous transluminal coronary angioplasty can relieve myocardial ischemia after unsuccessful CABG in the majority of patients.

Coronary angioplasty in patients with prior coronary artery bypass grafting

We studied the clinical and angiographic outcome of patients with prior coronary arterial bypass grafting who underwent percutaneous transluminal coronary angioplasty at the Royal Infirmary of Edinburgh. Over a 4 year period, 47 patients with prior bypass surgery underwent angioplasty of 23 stenotic graft sites and 37 stenotic sites of native vessels. The procedure was performed a mean of 31.3 months after surgery for recurrence of symptoms refractory to maximal medical treatment. Satisfactory angiographic results were achieved in 42 patients (58 stenotic grafts or native vessels). At a median follow up period of 18 months, 20 patients were symptomatically improved, but 22 patients experienced recurrence of symptoms a mean of 4.7 months after angioplasty, despite a good initial angiographic result. Overall, 4 patients had a repeat bypass grafting and 9 patients had a repeat angioplasty. Angioplasty can be used as an alternative to a repeat operation in patients with prior bypass grafting who experience recurrence of symptoms. Initial success rates are high and complication rates low. Restenosis or development of new lesions in the native circulation, and/or in the grafts, remain significant problems. Patients with a long asymptomatic interval (greater than 6 months) between the bypass operation and recurrence of symptoms are more likely to have better long-term results after successful angioplasty, perhaps because of slower progression of atherosclerotic heart disease.

Outcome following emergency coronary artery bypass grafting for failed elective balloon coronary angioplasty in patients with prior coronary bypass

To assess frequency and outcome of emergency coronary artery bypass grafting (CABG) for failed coronary angioplasty in patients with prior CABG, 2,136 elective angioplasty procedures in prior CABG patients were reviewed over a 10-year period. Emergency surgical revascularization was required in 19 patients (0.9%) with prior CABG, compared with 130 of 6,974 patients (1.9%) without prior CABG (p = 0.001). The interval from the most recent CABG to the failed coronary angioplasty was 6.8 years (range 1 to 16). Referral for emergency CABG was made on the basis of an acute closure not responding to repeat dilatation in 12 native coronary arteries and in 7 saphenous vein grafts. Severe hemodynamic instability after acute closure required the placement of an intraaortic balloon pump in 3 patients, including 2 who required cardiopulmonary resuscitation. A total of 34 saphenous vein grafts and 1 internal mammary artery graft were placed emergently. Three patients with high-risk features (3 prior CABG operations in 1 patient, single remaining vessel to heart in 2 patients) could not be weaned from cardiopulmonary bypass. The remaining 16 patients were discharged after a mean hospital stay of 16 days. Four patients developed new Q waves after CABG. At follow-up (mean 52 months, range 3 to 99), 1 patient died late from an acute myocardial infarction. The 15 survivors had no or mild angina and were free of further CABG. Thus, emergency CABG after failed angioplasty in patients with prior CABG is required infrequently. In patients without extreme high-risk features, emergency repeat CABG can be accomplished with good hospital and long-term results.

Coronary angioplasty for medically refractory unstable angina in patients with prior coronary bypass surgery

Percutaneous transluminal coronary angioplasty (PTCA) has been applied with good results to selected patients with unstable angina and to selected patients who have had prior bypass surgery. The population with prior bypass and unstable angina has not been specifically evaluated. This report reviews the results of angioplasty of 45 vessels in 34 patients with medically refractory unstable angina and at least one prior bypass heart surgery. Of these 34 patients, 32 had rest angina; 14 had resting electrocardiographic changes, all 34 were on aspirin 325 mg QD, 31 were on a calcium blocker, 22 were on a beta blocker, 9 were on intravenous nitroglycerin, and 5 required intraaortic balloon counterpulsation for temporary stabilization. Angioplasty of a vein graft was attempted in 17 patients; the left internal mammary was attempted in 4 patients; 24 native coronary arteries in 15 patients were attempted; 3 of the native arteries were protected left main arteries. Of the LIMA angioplasties, 3 were successful; in the 1 unsuccessful case, the occluded anterior descending artery was opened. Of the 17 vein grafts, 16 were successful: 1 had an acute occlusive syndrome and went to surgery with a balloon pump and bail out catheter; his recovery was uneventful. Of the 24 native artery angioplasties, 22 were successful: one patient was technically unsuccessful in the only vessel attempted; he went to semiemergent surgery and recovered uneventfully. In the other, a right coronary lesion was successfully dilated, but an occluded anterior descending artery was not opened. There were no deaths or in-hospital myocardial infarctions.(ABSTRACT TRUNCATED AT 250 WORDS)

Retrograde coronary angioplasty of isolated arterial segments through saphenous vein bypass grafts

Progression of native coronary artery disease proximal to the placement of saphenous vein grafts may leave arterial segments isolated by stenoses on either side. In 16 patients, we attempted coronary angioplasty in a retrograde direction through saphenous vein grafts to revascularize 17 isolated arterial segments. The retrograde dilatation was successful in 12 of 17 attempts (71%). Failure in 5 attempts was due to severe angulation between the graft insertion site and the retrograde proximal arterial limb. There were no major complications of these procedures. Symptoms and signs of myocardial ischemia were relieved following successful retrograde dilatation. Thus, retrograde dilatation through saphenous vein grafts provides another means of achieving complete revascularization using coronary angioplasty in patients with prior coronary bypass surgery.

Indications for and risks in reoperation for coronary artery disease

Seventy-one coronary artery bypass grafting (CABG) reoperations were performed during a 17-year period, comprising 2.7% of all CABG operations. The main indication (in 87%) was vein graft failure alone or combined with other causes. Progression of disease in native coronary arteries was the sole indication in only 4 of the 71 cases. There were seven perioperative deaths, mainly due to myocardial infarction. Significant perioperative complications arose in 36 cases, including intraoperative lesion of a previous left internal mammary graft (16.2%) or of the right ventricle or anterior descending branch of the left coronary artery (2.8%). Postoperative low output syndrome appeared in 13 patients (18.3%), in seven of whom myocardial infarction was verified. Postoperative bleeding required resternotomy in six cases (9.1%). Because of the heightened operative mortality and morbidity risks, indications for redo CABG should be individualized. A well functioning internal mammary artery graft may be a relative contraindication. Accurate knowledge of the previous operation is essential and, especially in young patients, the possibility of reoperation should be taken into consideration at initial CABG.

Reoperation after pericardial closure with bovine pericardium

To reduce the risk of damage to the anterior surface of the right ventricle after resternotomy, it has been recommended that the pericardium be closed with a patch after open heart operations. We have examined 4 patients undergoing resternotomy for the third time 3 to 8 years after bovine pericardium valve replacement. On each occasion the pericardium was closed with a patch of bovine pericardium. In all cases, the patch was frozen to the inner aspect of the sternum, increasing the difficulty of resternotomy. Histological examinations of the patches confirmed dense fibrous connective tissue, patchy calcification, and foreign body giant cell reaction. Bovine pericardium appears to increase the difficulty of repeat cardiac operations. We recommend its use be discontinued.

Use of the exercise test to predict prognosis after coronary artery bypass grafting

The objective of this study was to predict the prognosis of patients who become symptomatic after having undergone coronary artery bypass grafting (CABG) using clinical and exercise test responses. A retrospective analysis was performed of all veterans referred for clinical indications to a Veterans Administration Medical Center for a treadmill test after having undergone CABG. Of 2,044 patients who were exercise tested from April 1984 to May 1987, 296 had previously undergone CABG. Clinical data considered included age, sex, medication and symptom status, history of myocardial infarction, type of myocardial infarction and time from CABG. The exercise test responses considered were MET level, maximal heart rate, maximal systolic blood pressure, chest pain pattern and ST-segment response. During a 2-year follow-up after exercise testing, there were 15 deaths, 11 nonfatal myocardial infarctions, 6 repeat CABGs and 3 percutaneous transluminal coronary angioplasties. Although MET level and maximal heart rate were significantly related to prognosis and no patient who exceeded 8 METs died, the predictive power of these exercise test responses was low and ST-segment depression was not predictive at all. The inability of the exercise electrocardiogram to predict cardiac events in patients after CABG requires the use of other methods of testing to identify those who need invasive studies and intervention.

The clinical efficacy and scintigraphic evaluation of post-coronary bypass patients undergoing percutaneous transluminal coronary angioplasty for recurrent angina pectoris

The efficacy of percutaneous transluminal angioplasty in improving recurrent anginal symptoms and myocardial perfusion after coronary artery bypass graft surgery was assessed prospectively in 55 patients, of whom 50 had an initial angiographic and clinical success. Although 80% of those successfully dilated were initially free of angina at 23 +/- 11 months of follow-up, one half of these patients had recurrent angina. Although only 48% of the patient cohort had complete relief of angina, 94% had less angina than before dilatation and 86% were able to decrease antianginal medications. Fifteen patients with persistent or recurrent angina had from one to five repeat dilatations. After angioplasty, lung thallium uptake, the extent of abnormal scan segments, and the magnitude of redistribution in dilated lesions were significantly reduced (n = 24 patients). Redistribution defects were seen in 38% of patients on postangioplasty scans. All were associated with subsequent angina. Of various clinical, angiographic, exercise, and thallium-201 scan variables, only the presence of delayed redistribution was an independent predictor of recurrent angina. Restenosis was the most common underlying cause for this exercise-induced perfusion defect. Thus percutaneous coronary angioplasty performed as primary therapy for recurrent angina after bypass surgery is moderately successful in long-term follow-up for the amelioration of symptoms and enhancement of regional myocardial perfusion.

Early and late results of re-operation for coronary artery disease: a 13-year experience

A second coronary artery bypass grafting procedure was performed for recurrent angina in 119 patients between 1970 and mid-1983. Angiographic findings were assessed and computerized using the Brandt myocardial scoring system. The myocardial score was similar prior to the first and second operations. Graft failure was the most common indication for re-operation, either alone (48%) or in combination with progression of coronary artery disease (29%) or incomplete revascularization (10%). Progression of coronary artery disease alone was an indication in 9% and previous incomplete revascularization alone in 4%. The completeness of revascularization at the end of operation was analysed using a new index, the myocardial score/graft coverage rate. This showed that revascularization was less complete at the second operation than at the first (P less than 0.0001). The hospital mortality at re-operation was 2.5% and the peri-operative myocardial infarction rate was 9.2%. The follow-up period was 54 months (range 10-160 months). Actuarial survival was 94% at 5 years and 74% at 10 years. The average onset of recurrent angina was earlier after the second operation than after the first (P = 0.001). Using a cumulative actuarial curve, survival at 8 years was 85%, a further 6% of patients had undergone a third or fourth operation, and a further 25% were in NYHA Classes III or IV. Therefore 54% achieved a good or excellent result. It was concluded that re-operation is a worthwhile procedure.

Coronary reoperations

As coronary bypass surgery evolved from a procedure offered to good-risk patients into an intervention that is now applied to a spectrum of patients with many high-risk characteristics, so, too, reoperation for coronary surgery is now applied to an aging population with complicated atherosclerosis and abnormal left ventricular function. Despite our increased understanding of the factors that generate a need for reoperations and some potential avenues for preventing or delaying reoperations, the number of reoperations seems likely to increase. It is clear that the consistency of intraoperative myocardial protection must be improved; however, the favorable long-term results for these patients solidify the role of reoperation as an applicable intervention for patients with severe coronary atherosclerosis.

Percutaneous transluminal angioplasty in patients with prior myocardial revascularization surgery

Direct myocardial revascularization surgery using either the saphenous vein or internal mammary artery has become the definitive surgical treatment for coronary artery occlusive disease. Certain patients who have undergone these procedures, however, have recurrent myocardial ischemia due to progression of disease in unbypassed vessels, to obstruction in the arteries distal to the insertion of the bypass conduit, or to disease of the conduit itself. Balloon angioplasty may be used to relieve myocardial ischemia in these situations; however, initial studies suggested a low primary success rate coupled with excessive mortality and morbidity. Improvements in patient selection, equipment and technical expertise now allow angioplasty to be performed in this patient population with results comparable to that in the general coronary angioplasty population. Of the 3,016 angioplasty procedures performed between September 1980 and June 1987, 236 patients had previously undergone revascularization surgery. The primary success rate was 93% (390 of 419 stenoses successfully dilated). Overall, clinical restenosis was observed in 39%, including a 43% restenosis rate in patients undergoing only saphenous vein graft angioplasty. This did not differ appreciably from the restenosis rate in postbypass patients undergoing angioplasty of only native vessels (37%) or internal mammary arteries (42%). Emergency revascularization surgery was required in 7 of 236 patients (3%), each of whom had myocardial infarction. One of 236 patients (0.4%) died. Thus, angioplasty may be used to relieve recurrent myocardial ischemia in patients with prior direct myocardial revascularization procedures with a high initial success rate and acceptable risk. Early (less than 6 months) restenosis is not infrequent and remains the largest obstacle to a satisfactory clinical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

The changing profile of the patient undergoing coronary artery bypass surgery

The first 100 consecutive patients undergoing isolated coronary artery bypass surgery in 1975 were evaluated with respect to the incidence of operative risk factors and outcome. When compared with an identically selected group from 1985, there was significant worsening of the preoperative condition over the decade with regard to mean age (p less than 0.0005), presence of congestive heart failure (p less than 0.05), left ventricular dysfunction (p less than 0.05), severity of coronary artery disease (p less than 0.001) and incidence of emergency operation (p less than 0.05). More patients in 1985 had associated medical diseases such as diabetes (p less than 0.01) and chronic lung disease (p less than 0.005). There was an increase in the occurrence of vascular diseases (hypertension, renal dysfunction, peripheral vascular and cerebrovascular disease) (p less than 0.05). Overall operative mortality increased from 1 to 8% (p less than 0.05) over the decade. Despite the deterioration in the clinical profile of the patient undergoing coronary bypass surgery, elective procedures were still performed with low mortality. The significant increase in overall mortality was chiefly in patients undergoing emergency operation (p less than 0.05). There were also increases in operative morbidity including low output syndrome (p less than 0.01) and respiratory (p less than 0.005) and neurologic (p = 0.06) complications.

Coronary artery reoperations. Early and late results in 101 patients

Coronary artery reoperation was performed on 101 patients between 1972 and 1985. The resternotomy was associated with major hemorrhage in 12 cases. Of 29 patent internal mammary artery (IMA) grafts, 11 (38%) were damaged during mobilization of the left ventricle. At reoperations performed more than a year after the initial operation, increased graft blood flow compared with the first operation was observed in IMA but not in vein grafts. There were six early deaths (6%). The 5-year survival rate, inclusive of early mortality, was 90%. After a median of 2.5 years, 82% of the patients reported symptomatic improvement and 22% were completely free from angina, but full physical fitness was restored in only 3%. Excluding the patients of retirement age, 35% were able to resume work after the reoperation. Coronary artery reoperation should be considered only for patients with severe angina, because of the increased surgical risk and the lower likelihood of completely relieved symptoms. Presence of a patent IMA graft necessitates special caution.

Reoperation for coronary artery bypass grafting: anesthetic challenge

The problem of caring for patients undergoing reoperative coronary revascularization is one that cardiac anesthesiologists will face with increasing frequency. Many thousands of CABG procedures continue to be performed annually with ever-increasing survival rates. Consequently, the population at risk for reoperative CABG is growing, while surgical intervention necessarily follows apace. As one recent long-term, retrospective study showed, patients surviving 12 years after CABG have a reoperative rate of 17.3%. Physicians caring for these patients must recognize that they are not seeing patients with routine CAD, but with a different entity: coronary graft disease (CGD). These patients with CGD are different in many ways from those with native CAD, and these differences must be taken into account when planning for their perioperative care. Cardiologists have strived to check the growth of CGD by aggressive emphasis on modification of coronary risk factors such as tobacco use, hypertension, and hyperlipidemia. In addition, recent interest has been focused on a pharmacologic approach via the platelet-prostaglandin system. Surgeons have also attempted to reduce the incidence of CGD by recognition that significantly improved long-term patency rates can be achieved by the use of the internal thoracic artery as a bypass conduit. Consequently, an expanded role for this vessel in the form of free, sequential, and bilateral ITA grafting is currently being advocated as a surgical solution to the problem of CGD. In contrast, the anesthesiologist probably has little to add to the prevention of CGD, but may be able to contribute to a favorable outcome at reoperation. The medical variables and preoperative characteristics that make reoperative CABG patients different from those presenting for primary CABG should be recognized. A firm appreciation of the nature of graft disease, as well as the surgical intricacies required for correction, can only serve to improve the care offered during these often complex operations. Aggressive, invasive hemodynamic monitoring, constant vigilance for signs of early ischemia, and preparedness for prebypass hemorrhage and postbypass ventricular dysfunction should be made. Furthermore, if anesthesiologists are to contribute to an improved outcome in these patients, strategies must be developed to attenuate cerebral and myocardial damage resulting from hemorrhage and atheroembolic catastrophies that appear to be frequent complications in these challenging surgical patients.

The healing characteristics of autogenous saphenous vein used in the reconstruction of previously implanted arterial saphenous vein grafts

Aortocoronary saphenous vein grafts with early isolated stenoses pose the technical problem of how to deal with these grafts at reoperation. The advisability of using a portion of old graft when reconstructing these grafts was examined. An experimental model was devised in which the anatomical and pathological interfaces between fresh vein and previously inserted vein were studied. Superficial femoral artery from the thigh of 15 dogs was replaced by reversed autogenous saphenous vein. Four months later, the animals were divided into two groups. Group 1 consisted of 8 animals that underwent transection and reimplantation of the middle 4 cm of the vein graft in exactly the same position in which it had been. In Group 2, the 7 animals had the middle 4 cm of the graft replaced with newly harvested reversed saphenous vein. Six months after initial vein graft implantation, the animals were studied. No critical stenoses were seen in the grafts. Pathological study of Group 1 grafts revealed fibrous graft disease of uniform severity throughout the graft, thereby demonstrating that new anastomoses in an old graft do not affect graft disease. Group 2 grafts revealed that the severity of disease in the new interposed segment of the vein graft was less than in the old retained portions of the graft. No untoward reaction causing acceleration of graft disease occurred between old and new vein. Operations using undiseased portions of old vein grafts should be considered a viable option in repeat coronary revascularization for early stenoses.

Incidence, risk, and outcome of reintervention after aortocoronary bypass surgery

Reintervention was required in 123 (12%) individuals during a follow up (mean 7.5 years, range 5-14.5) of 1041 patients with consecutive, isolated, first aortocoronary bypass operations. In 89 patients the intervention was a repeat bypass operation, in 24 it was angioplasty, and 10 had both. Procedure related mortality was significantly higher at reintervention (5.6%) than at the primary operation (1.2%). Survival probability after a single bypass procedure was 90% at six years and 82(3)% at nine years. Corresponding figures six and nine years after reintervention were 89(6)% and 87(7)% respectively. Stepwise multivariate analysis showed that survival was significantly correlated with left ventricular function (rate ratio 1.82) and with extent of vascular disease (rate ratio 1.80) but not with reintervention (rate ratio 1.45). Symptomatic improvement occurred in 89% of the survivors with or without reintervention. Repeat procedures are often necessary after coronary artery bypass grafting but they appear to provide appreciable relief of symptoms without reducing any long term improvement in survival brought about by the original operation.

Management during reoperation of aortocoronary saphenous vein grafts with minimal atherosclerosis by angiography

The proper management of saphenous vein grafts showing minimal angiographic evidence of atherosclerosis at the time of reoperation for progressive atherosclerosis in the native coronary circulation or for severe atherosclerosis in other saphenous vein grafts is uncertain. Following the occlusion of vein grafts in 2 patients 7 and 12 years after operation but only 2 years after arteriography demonstrated no major abnormalities in the grafts, we adopted a policy of elective replacement of all saphenous vein grafts, irrespective of angiographic findings, when reoperation was necessary 5 or more years after the initial operation. Between July, 1984, and May, 1985, 16 patients had repeat coronary artery bypass grafting 6 to 13 years (mean, 9 years) after the initial procedure. Complete revascularization was carried out in all patients. In each, it included replacement of at least 1 saphenous vein graft showing no severe obstruction (less than 30% of the luminal diameter) and no (5 patients), minimal (8), or moderate (3) luminal irregularities by angiography. By pathological examination, 3 of the grafts had minimal, 5 had moderate, and 8 had severe atherosclerotic changes present. These changes were generally more diffuse than those observed by angiography. Because angiography underestimates the severity of the atherosclerotic degeneration in saphenous vein grafts and because of the propensity of the atherosclerotic disease to progress at an unpredictable rate, we recommend routine replacement of all saphenous vein grafts at the time of reoperation if done 5 or more years after the initial procedure.

Angioplasty for aortocoronary bypass graft stenosis

During the period November 1979 to October 1984, 19 patients at our institution underwent balloon angioplasty of partial or complete obstruction of aortocoronary artery saphenous vein bypass grafts. The procedures were performed a mean of 38 months after a coronary bypass operation to relieve recurrent angina of at least class 2 in the Canadian Cardiovascular Association functional classification. Graft angioplasty was successful in 16 of the 19 patients, and the location of the lesion (in the origin, body, or distal insertion of the graft) did not seem to be an important factor in achieving a successful result. At a mean follow-up interval of 20 months (range, 1 to 40 months), 14 patients had symptomatic improvement. Two patients required late repeat operation and four had repeat angioplasty because of restenosis. Our experience supports the use of balloon angioplasty in selected patients with bypass graft stenosis, but restenosis remains a substantial problem.

State of the vein grafts, native coronary arteries, and myocardium and principal cause of death in patients dying after aortocoronary bypass grafting

Fifty five patients with 108 coronary bypass saphenous vein grafts were studied at necropsy. The mean duration of the grafts was 153 days (SD 516). The luminal narrowing of the native coronary arteries proximal to, at, and distal to the vein graft anastomoses and the narrowing of the non-grafted arteries were evaluated planimetrically. Twenty nine per cent of coronary arteries distal to graft anastomoses showed at least 76% narrowing and 50-75% occlusion was seen in 39% of such arteries. Fifty three per cent of non-grafted arteries showed at least 76% luminal narrowing and 26% had 50-75% narrowing. Six patients (11%) had surgically induced dissection of coronary arteries. Seventy seven vein grafts (71%) showed no appreciable luminal narrowing. Problems related to operative technique caused 30% of the deaths.

Follow-up clinical results in patients undergoing percutaneous transluminal coronary angioplasty

Complete follow-up data were obtained from 229 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) between 1979 and 1982 (mean follow-up 14 months, range 6 to 37). Single-vessel disease was present in 143 and multivessel disease in 86. PTCA was successful in 153 patients (67%). Failure was followed initially by bypass surgery in 59 and by continued medical therapy in 17. After successful PTCA, 90% of patients were improved subjectively and 74% were asymptomatic at follow-up. After unsuccessful PTCA but prompt bypass, 90% were improved subjectively and 85% were asymptomatic. Among the 229 patients, 39 (17%) required an additional intervention because of angina during follow-up; 15 of these had repeat PTCA and 18 had bypass surgery. Among patients with successful PTCA, revascularization was complete in 77% and partial in 23%. The completeness of revascularization with PTCA had a significant impact on follow-up. The follow-up data of patients with successful single-vessel PTCA and of those with multivessel disease with complete revascularization were similar. When the patients with complete revascularization were compared with those with multivessel disease but incomplete revascularization, the follow-up data were characterized by a higher incidence of angina or need for bypass surgery in the latter group (63%) than in the former group (29%); those with incomplete revascularization also had a significantly reduced event-free survival.

Reoperation for angina after previous aortocoronary bypass surgery

A retrospective study was carried out of the outcome of 102 patients who underwent a second operation for myocardial revascularisation, necessitated by persistence or recurrence of intractable angina after their first coronary bypass procedures. Operative mortality was 2%. During follow up of the survivors (mean interval 36.4 months) five died, two after further operation, and five underwent further surgery. Sixty eight patients reported an improvement in their symptoms, 57 of whom claimed to have little or no angina. Less favourable results were recorded for those patients reviewed with longer follow up. No useful indicators of prognosis were identified. The problem of angina in patients who have already received bypass grafts is likely to increase as more revascularisation surgery is performed. Reoperation offers a reasonable prospect of helping some of these patients, but not all will be suitable. Their long term prognosis remains uncertain.

Comparison of operative mortality and morbidity for initial and repeat coronary artery bypass grafting: The Coronary Artery Surgery Study (CASS) registry experience

The National Heart, Lung, and Blood Institute's Coronary Artery Surgery Study (CASS) registry population was reviewed to allow comparison of operative mortality and morbidity rates for initial and repeat coronary artery bypass grafting (CABG) procedures. Standardized data collection was employed in CASS during patient entry (July 1, 1974, to May 31, 1979) and follow-up (ended November 30, 1982). Initial CABG was performed on 9,369 patients. Mean follow-up was 60.5 months. Repeat CABG was required in 283 patients (3.0%). The mean interval between operations was 39.3 months. Individuals needing reoperation tended to be young (p less than 0.0001) and female (p less than 0.002) and to have less extensive coronary artery disease (p less than or equal to 0.0001), less left ventricular impairment (p less than 0.0001), less evidence of congestive heart failure (p = 0.006), and fewer coronary vessel systems bypassed at the first operation (p less than 0.0001). Repeat CABG carried an increased risk of death compared with initial CABG (5.3% versus 3.1%, respectively; p less than 0.05). However, the rates of perioperative myocardial infarction (6.4% for repeat and 5.8% for initial CABG) and of all surgical complications combined (30.6% versus 27.9%) were not significantly different from those at initial CABG.

Patient care problems in patients undergoing reoperation for coronary artery grafting surgery

Over the past six years there has been a 15-fold increase in the number of patients requiring reoperation coronary artery bypass grafting (RCABG) surgery at the University of Alabama in Birmingham. To determine the perioperative risk, a retrospective chart survey of one calendar year's (1981) experience was made comparing the 58 RCABG patients with 59 cohorts undergoing primary operation. All patients were anaesthetized with diazepam, fentanyl and halothane or enflurane anaesthesia. Preoperative evaluation revealed by history that the incidence of unstable angina and digoxin use were greater (p = 0.05) in the RCABG patients. Cardiac catheterization revealed a higher incidence (26 vs 89 percent) of left main coronary disease in controls and similar indices of left ventricular function (wall abnormalities, ejection fraction and LVEDP). Operating and bypass times were longer (p less than 0.01) for RCABG patients and there was a trend for greater (p = 0.08) use of dopamine in the RCABG patients. CK-MB release was significantly (p less than 0.05) greater in RCABG patients. Serious postoperative complications (CK-MB greater than or equal to 15 IU/L, low cardiac output, and death) were significantly (p = 0.02) greater in the RCABG group. It is concluded that RCABG patients represent a greater risk of complications and that new strategies for improving myocardial protection need to be developed to reduce the risk.