Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction.

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.

Stenting versus thrombolysis in acute myocardial infarction trial (STAT).

OBJECTIVES: We sought to directly compare primary stenting with accelerated tissue plasminogen activator (t-PA) in patients presenting with acute ST-elevation myocardial infarction (AMI). BACKGROUND: Thrombolysis remains the standard therapy for AMI. However, at some institutions primary angioplasty is favored. Randomized trials have shown that primary angioplasty is equal or superior to thrombolysis, while recent studies demonstrate that stent implantation improves the results of primary angioplasty. METHODS: Patients presenting with AMI were randomly assigned to primary stenting (n = 62) or accelerated t-PA (n = 61). The primary end point was the composite of death, reinfarction, stroke or repeat target vessel revascularization (TVR) for ischemia at six months. RESULTS: The primary end point was significantly reduced in the stent group compared with the accelerated t-PA group, 24.2% versus 55.7% (p < 0.001). The event rates for other outcomes in the stent group versus the t-PA group were as follows: mortality: 4.8% versus 3.3% (p = 1.00); reinfarction: 6.5% versus 16.4% (p = 0.096); stroke: 1.6% versus 4.9% (p = 0.36); recurrent unstable ischemia: 9.7% versus 26.2% (p = 0.03) and repeat TVR for ischemia: 14.5% versus 49.2% (p < 0.001). The median length of the initial hospitalization was four days in the stent group and seven days in the t-PA group (p < 0.001). CONCLUSIONS: Compared with accelerated t-PA, primary stenting reduces death, reinfarction, stroke or repeat TVR for ischemia. In centers where facilities and experienced interventionists are available, primary stenting offers an attractive alternative to thrombolysis.

Profile of the cardiovascular specialist physician workforce in Canada, 2004.

The Canadian Cardiovascular Society (CCS) examined the demand for cardiovascular care, the supply of specialist physicians to provide that care and physician survey data on human resource issues, including workload, wait times, satisfaction and future intentions. The CCS used data from the National Physician Survey 2004, the CCS Cardiovascular Specialist Physician Workforce Survey 2001, the Canadian Medical Association's Physician Resource Evaluation Template and procedural volumes from the Canadian Institute for Health Information to analyze key human resource planning issues for cardiologists and cardiac surgeons. There are indications in the 2004 survey data that the average workload continues to be very heavy, with an average workweek of between 55 h (cardiologists) and 64 h (cardiac surgeons), and an additional on-call responsibility of between 106 h (cardiologists) and 196 h (cardiac surgeons) per month, of which 38 h (cardiologists) to 45 h (cardiac surgeons) are spent with patients. As a result, many patients are waiting too long for nonurgent referrals. In addition to the toll that this heavy workload exacts from the current workforce and the long wait times for nonurgent referrals, the workload may also compromise the profession's ability to attract physicians into cardiovascular care. Medical graduates, particularly female graduates, tend to consider workload flexibility and predictability when choosing a specialty area. Supply projections already show a decline in the number of cardiovascular specialists per 100,000 elderly population over the next 15 years. If cardiology and cardiac surgery are perceived by female medical graduates (which now make up over 50% of all graduates) as unattractive areas of specialization, the profession may have difficulty attracting needed new entrants in the future. The CCS Workforce Project Team endorses and supports the 2003 Canadian Medical Association's recommendation for the federal government to establish an independent institute for health human resources to foster and conduct research on the supply, mix, distribution and sustainability of Canada's health workforce. The CCS should also renew its commitment to invest in related activities to improve access to cardiovascular care. The CCS Workforce Project Team also believes that the profession's ability to recruit and retain new medical graduates will depend on how well it addresses the identified quality of work life issues.

Intravenous dipyridamole-induced myocardial ischemia during percutaneous transluminal coronary angioplasty in humans.

Percutaneous transluminal coronary angioplasty was used as a model of controlled myocardial ischemia to study the effect of intravenous dipyridamole on myocardial ischemia and coronary hemodynamics in 10 patients. All patients had 1-vessel coronary artery disease with visualized collaterals. Intravenous dipyridamole increased myocardial ischemia during inflations. ST elevation, as measured by intracoronary electrogram, increased significantly from the control inflation to the second inflation after dipyridamole injection (0.05 +/- 0.23 vs 0.44 +/- 0.43 mV, p less than 0.03). Of the 10 patients, 8 developed new or more severe angina with subsequent inflations after dipyridamole. The pulmonary artery wedge pressure increased significantly from the control inflation to the fourth inflation (15 +/- 8 vs 20 +/- 9 mm Hg, p less than 0.05). The coronary wedge pressure showed a decreasing trend with subsequent inflations after dipyridamole but did not reach statistical significance. The double product (heart rate X blood pressure) was not significantly altered by dipyridamole. The findings indicate that intravenous dipyridamole increases myocardial ischemia during balloon occlusion. The constancy of the double product and the trend toward a decrease in coronary wedge pressure suggest that dipyridamole may induce ischemia by reducing the amount of collateral flow through a coronary steal phenomenon.

Predictors of long-term outcome after stent implantation in a saphenous vein graft.

Stenting of saphenous vein graft (SVG) lesions is associated with significant clinical events at late follow-up. We sought to determine predictors of clinical outcome after this procedure. One hundred twenty-eight balloon-expandable stents were implanted in the SVGs of 106 patients. Baseline clinical and angiographic characteristics were analyzed. All grafts, including those not stented, were scored for extent of disease involving the luminal surface of the graft, and for the presence of low profile lesions (< 50% graft stenosis) and/or high profile lesions (> or = 50% graft stenosis). The in-hospital success rate was 98.1%. Before discharge, no patient died, required bypass surgery, or had repeat angioplasty of the same graft. Follow-up was obtained on all the patients. At a median of 18 months, 15% had died, 17% had experienced myocardial infarction, 20% had required repeat bypass surgery, and 37% needed repeat angioplasty to either the same site or a different lesion. Event-free survival was recorded in only 44% of the patients. The cumulative Kaplan-Meier survival at 2.4 years was 78.7%. Using the Cox proportional hazards model, predictors of survival were the absence of a high profile lesion in any nonstented patent graft (p = 0.004), and the use of lipid-lowering agents at follow-up (p = 0.01). Stenting SVG lesions can be performed with a high degree of procedural success, but at long-term follow-up there is a high rate of cardiac events. The absence of a high profile lesion in any nonstented patent graft is the strongest predictor of survival.

Usefulness of intracoronary stenting in acute myocardial infarction.

Data on the feasibility, safety, and clinical outcome of intracoronary stenting in acute myocardial infarction (AMI) are limited. This study examined the immediate angiographic results and the early and late outcomes in 32 patients who had stenting during AMI. Coronary angiograms recorded at the time of stenting were reviewed with quantitative measurements obtained on the "target" coronary lesion before and after stenting. Immediate angiographic success was achieved in 30 patients (94%). The minimal luminal diameter increased from 0.36 +/- 0.37 to 2.58 +/- 0.41 mm (p<0.0001). Two patients died in the hospital. Of the remainder, none had reinfarction or required bypass surgery, whereas 2 required repeat coronary angioplasty for recurrent ischemia. Although thrombus at the infarct-related coronary lesion was initially detected in 41% of the patients, its presence was not associated with adverse procedural outcome. Only 1 patient had persistent thrombus after stenting, which resolved with intracoronary urokinase. At a mean follow-up of 6.1 +/- 4.1 months, there was 1 additional cardiac death, and no patient had AMI or required repeat coronary angioplasty or bypass; among the 29 survivors, 86% were free of angina. Thus, intracoronary stenting of the infarct-related artery in the setting of AMI is associated with excellent immediate angiographic success and a favorable clinical outcome, and remains an option even in the presence of thrombus.

Minimally invasive coronary artery bypass: a series with early qualitative angiographic follow-up.

BACKGROUND: Notwithstanding the advantages offered by minimally invasive coronary bypass, valid concerns have been raised about the technical accuracy of the distal anastomoses that can be fashioned on a beating heart. The main objective of our study was to undertake early and complete qualitative angiographic graft analysis in all patients undergoing this procedure. METHODS: All enrolled patients (25) from January to October 1996 who had bypass done by one surgeon via left minithoracotomy (19) or median sternotomy (6) on a beating heart underwent postoperative angiography within 4 to 6 hours. These angiograms were then reviewed for qualitative analysis and compared with a similar series done under conventional cardioplegic arrest. RESULTS: There was 97.5% graft patency (28/29) and no anastomotic occlusions. One internal thoracic artery was damaged. There was no mortality and no perioperative myocardial infarctions. All patients are alive and symptom free. The follow-up is 100% complete and ranges from 15 days to 11 months. Of the 26 anastomoses that could be assessed, 21 (81%) were grade A and 5 (19%) were grade B. In comparison, 24/25 (96%) of the anastomoses fashioned on an arrested heart by the same surgeon were grade A (p = 0.175). CONCLUSIONS: Minimally invasive coronary bypass can be carried out effectively and safely in a select group of patients, and the development of stabilizing devices and proper instrumentation should further improve results.

Early and follow-up angiography in minimally invasive coronary bypass without mechanical stabilization.

BACKGROUND: This study was undertaken to assess the early and late outcome of coronary anastomosis constructed on a beating heart without the help of mechanical stabilization. METHODS: All consecutive patients (51) from January 1996 to September 1997 who had bypass done by one surgeon using a left minithoracotomy (39) or median sternotomy (12) on a beating heart with occlusive local snares without mechanical stabilization underwent follow-up angiography early (100%) (within 6 hours) and late (63.5%) at a mean of 9.6+/-4.48 months (range, 3.3 to 19.1 months). RESULTS: The cumulative late patency was 95.4% (83 of 87 patients), with two early and two late occlusions. There was no early or late mortality or perioperative myocardial infarction. Two patients (3.9%) developed recurrent angina. Four anastomotic irregularities (4 of 32 patients, 12.6%) have cleared up on follow-up angiography. There was no evidence of late stenosis at the snare sites used for local occlusion. CONCLUSIONS: Minimally invasive coronary bypass is safe and effective. Early angiographic abnormalities should be interpreted with caution and we could not demonstrate any long-term deleterious effects of local snaring.

Reperfusion hemorrhage following PTCA and thrombolysis for left main coronary artery occlusion.

Myocardial reperfusion hemorrhage has been reported in humans but rarely after percutaneous transluminal coronary artery angioplasty (PTCA) of occluded vessels and not after the reopening of left main occlusions. Three patients with infarct and cardiogenic shock and reperfusion hemorrhages after PTCA, with or without streptokinase infusion and reopening of acutely thrombosed left main coronary arteries are reported here. The effect of the reperfusion 24,9 and 7 h after symptom onset and 24,25 and 3 h before death is examined.

Ongoing role of pulmonary embolectomy.

Pulmonary embolism remains a frequent and often fatal disorder. For the majority of patients, anticoagulation with heparin followed by warfarin represents the primary mode of treatment. Thrombolytic therapy is recommended for the patient with massive pulmonary embolism that has produced hypotension. Embolectomy is reserved for the patient with post embolic systemic hypotension who has an absolute contraindication to thrombolysis or who deteriorates despite thrombolytic therapy. Following successful embolectomy the surgeon must treat the complications of the surgery and prevent recurrence. Complications include cerebral infarction, pulmonary infarction and endobronchial hemorrhage, right ventricular failure, local or systemic bleeding and venous stasis. A case of successful pulmonary embolectomy with a complicated postoperative course is presented and the pathophysiology and treatment of the complications are discussed.

Rates of cardiac catheterization, coronary angioplasty and coronary artery bypass surgery in Canada (1991).

OBJECTIVE: To determine the rates of and waiting lists for cardiac catheterization, percutaneous transluminal coronary angioplasty (PTCA) and open heart surgery among adults in Canada between January 1, 1991 and December 31, 1991. Furthermore, a comparison was made with a previous survey performed in 1988. DESIGN: Mail survey. Participants were the directors of all 46 adult cardiac catheterization laboratories and representatives from all 33 adult cardiovascular surgery programs in Canada. MAIN RESULTS: A total of 69,914 cardiac catheterizations was performed during this period, a rate of 256/100,000 population. The mean waiting times for elective procedures were weighted to allow for the differences between centres in the number of patients awaiting the procedures. The mean wait for elective cardiac catheterization was 8.5 weeks, precisely the same as it had been in 1988. There were 14,617 PTCA procedures performed, a rate of 54/100,000 population. This rate had increased from 39,100,000 in the previous survey. The mean wait for elective PTCA was 9.2 weeks. A total of 13,618 coronary artery bypass procedures were performed, a rate of 50/100,000 population. The mean wait for elective coronary artery bypass surgery was 213 weeks, with the longest wait occurring in Quebec at 34 weeks. CONCLUSION: Rates for cardiac catheterization increased by 8.5% between 1988 and 1991. The mean waiting time for this procedure did not change significantly across the country in this interval. The rate of PTCA increased by 38.5% during this same time interval. The rate of open heart procedures across the country increased by 20.6%. The waiting period for these specialized cardiac procedures remains excessive, particularly for open heart surgery.

Fatal angioedema associated with enalapril.

A 65-year-old male with a long history of congestive heart failure presented to the emergency room with facial swelling 7 h after the first dose of enalapril. He was treated with diphenhydramine and hydrocortisone which improved his angioedema. However, there was a profound relapse of the angioedema followed by respiratory arrest. He suffered severe anoxic brain damage and died five days later. It is likely that the long half-life of enalapril lead to this rebound phenomenon. Enalapril induced angioedema is reviewed with suggestions for management.

Coronary stenting in acute myocardial infarction--patency demonstrated postmortem.

This report describes a patient with an acute anterior myocardial infarction treated by primary angioplasty and stenting of the infarct-related artery. The patient died 48 h later and at postmortem examination, patency of the stented artery was demonstrated, despite the adverse conditions which preceded death.

Stenting of the left main coronary artery in the setting of acute myocardial infarction.

Coronary artery bypass grafting is the treatment of choice for significant left main coronary artery disease. A patient with an occluded left main coronary artery in the setting of myocardial infarction, who was given streptokinase and subsequently managed with intracoronary stenting, is reported.

Paradoxical embolism-in-transit: diagnosis and surgical treatment.

Paradoxical embolism-in-transit is an uncommon presentation of the thromboembolism complex. The advent of echocardiography has permitted its antemortem diagnosis and serves to guide treatment; this is illustrated by the case of a 51-year-old female who presented with paradoxical embolism-in-transit and pulmonary embolism following craniotomy. Echocardiography demonstrated mobile clot straddling the atrial septum and embolus in the right pulmonary artery. Surgery successfully removed all clots as demonstrated by intraoperative echocardiography, and the patient had an uneventful recovery.

Late reassessment of percutaneous transluminal coronary angioplasty results: clinical, exercise and angiographic follow-up.

One hundred and forty-five patients underwent percutaneous transluminal coronary angioplasty (PTCA) in the authors' hospital between 1981 and 1983. Four have since died and all but one of the remainder were accounted for at follow-up 41 +/- 12 months later. Recurrence of angina was present in 28% of patients having successful PTCA versus 33% of patients with surgery for failed PTCA. Use of antianginal drugs and return to work was similar in the two groups. Mean treadmill time, peak heart rate, incidence of treadmill angina and exercise thallium-201 defects were not different in the two groups. Late follow-up coronary angiography in 60 patients who had successful PTCA showed a significant decrease in mean stenosis of the dilated segment from 31 to 23%. Of 25 patients who had late angiography after failed PTCA, three had satisfactory patency of the dilated segment. New significant coronary stenosis was seen in only 17% of patients not having coronary bypass surgery.

Local morphologic effects of coronary artery balloon angioplasty.

The morphologic effects of percutaneous transluminal coronary artery balloon angioplasty (PTCA) on atherosclerotic vessels is described in six patients who died at varying intervals after the procedure (four early and two late). In the early group (less than one week post PTCA) one patient died because of electromechanical dissociation during emergency PTCA for evolving infarct; in the three other patients PTCA was performed for left main occlusion and cardiogenic shock with deaths 3, 24 and 25 h after PTCA. The two late deaths were patients who died one and nine months after PTCA from unrelated causes. There were 12 sites of balloon inflation in the six patients, all in left main, isolated marginal or left anterior descending arteries. Post mortem examinations, with in toto serial sectioning of the ballooned coronary arteries, revealed a number of local morphologic changes. Plaque fractures and disruptions of the arterial wall to variable depths were observed. At four sites these fractures were through media, and at one site was associated with a large dissection. These cases had only small epicardial hemorrhages or reactive adventitial changes associated with these deep fractures. Four of the six patients had intramural arterial emboli (athero/thrombo/calcium/foreign body). These findings confirm that a large part of the effect of PTCA is due to physical disruption of plaque and underlying native vessel.

Potential cardiotoxicity with the use of DuP-941: a case report.

OBJECTIVE: To describe the clinical and pathological features of a patient with probable cardiotoxicity related to a newer chemotherapeutic agent, DuP-941. PATIENT AND METHODS: A 42-year-old woman with metastatic breast carcinoma treated with only DuP-941 developed, and died of, heart failure for which no other explanation was apparent. RESULTS: Clinically the patient's heart failure resembled that associated with anthracycline cardiotoxicity, as did the pathological features seen at autopsy. CONCLUSION: DuP-941 is a new chemotherapeutic drug that may supplant some uses of the anthracyclines because the former may have less cardiotoxicity. This report suggests that in some cases DuP-941 may have cardiotoxic effects as well.

Importance of timing of treadmill predictors for risk stratification after myocardial infarction: a five year follow-up study.

The prognostic value of information derived from clinical characteristics and exercise treadmill tests performed before discharge and repeated at three months was evaluated in 205 consecutive patients followed for five years. Recurrent myocardial infarction, unstable angina and mortality were tabulated. Survival was analyzed by the Kaplan-Meier life-table method and the Cox regression model. The major difference between the predischarge and three month intervals was the failure of exercise-induced ST depression to predict mortality from the predischarge test. However, it was predictive of mortality at three months when 76% survived five years with a positive ischemic response compared to 94% with a negative response (P less than 0.0005). In contrast, resting ST depression of at least 1 mm was associated with a very poor five year survival rate of 58.3% and 50% when assessed at both predischarge and three months (P less than 0.0005 and P less than 0.004, respectively). Selected univariately at the predischarge interval, the following characteristics were ranked in descending order of predictive power for five year mortality by discriminant analysis: history of previous infarction; exercise capacity; and ST depression on resting ECG greater than 1 mm. At three months, the same characteristics were selected. However, recurrent infarction and unstable angina were not predictable at either interval by any clinical or treadmill variable. Characteristics tending to reflect poor exercise capacity are stronger predictors of five year outcome than exercise-induced ischemia. While predischarge exercise testing for ST segment response failed to predict survival, this variable showed improved predictive power with repeat testing at three months.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary stenting in unstable angina: early and late clinical outcomes.

OBJECTIVE: To examine the procedural and long term success of coronary stenting in patients presenting with unstable angina and the effect of warfarin on the clinical outcome of these high risk patients. DESIGN: A nonrandomized, retrospective analysis of patients presenting with unstable angina. SETTING: A tertiary care, Canadian university-affiliated teaching hospital. PATIENTS: Of 1250 patients who underwent percutaneous transluminal coronary angioplasty between January 1994 and June 1995, 365 underwent coronary stenting. The study population consisted of the 156 patients presenting with unstable angina who underwent coronary stenting. Patients with Canadian Cardiovascular Society class IV and postinfarction angina were included. INTERVENTIONS: Stent delivery by standard techniques to the target lesion was successful in all patients. At discharge, 88 patients were prescribed warfarin, ticlopidine and acetylsalicylic acid (ASA); the remaining 68 patients received only ticlopidine and ASA. Late clinical outcomes were assessed by telephone interview. RESULTS: The overall procedural success rate was 96%. One patient died in hospital (0.6%). Other events were abrupt closure (1.9%), myocardial infarction (1.9%) and urgent bypass surgery (1.9%). During follow-up, target vessel reintervention was needed in 19.6% of patients. Early and late clinical outcomes did not differ significantly between anticoagulated patients and those treated with antiplatelet agents alone, but anticoagulated patients had a significantly longer hospital stay. CONCLUSIONS: Coronary stenting in patients with unstable angina was associated with excellent procedural success and favourable late clinical outcomes. Warfarin added no apparent additional clinical benefit to antiplatelet agents in this high risk population.