Airlie Cameron

Coronary Bypass Surgery with Internal-Thoracic-Artery Grafts — Effects on Survival over a 15-Year Period

BACKGROUNDnAortocoronary bypass surgery has been performed most often with the patients saphenous vein as the conduit. The internal-thoracic-artery graft, which has superior patency rates, has been shown to have clinical advantages, but it is not known how long these advantages persist.nnnMETHODSnWe identified all the patients in the registry of the Coronary Artery Surgery Study who had undergone first-time coronary-artery bypass grafting. Those with internal-thoracic-artery bypass grafts (749 patients) were compared with those with saphenous-vein bypass grafts only (4888 patients) with respect to survival over a 15-year follow-up period.nnnRESULTSnIn a multivariate analysis to account for differences between the two groups, the presence of an internal-thoracic-artery graft was an independent predictor of improved survival and was associated with a relative risk of dying of 0.73 (95 percent confidence interval, 0.64 to 0.83). This improved survival was also observed in subgroups including patients 65 years of age or older, both men and women, and patients with impaired ventricular function. The survival curves of the two groups showed further separation over the years of follow-up, with a more marked downsloping after eight years in the curve for the group with saphenous-vein grafts only than in that for the group with internal-thoracic-artery grafts.nnnCONCLUSIONSnAs compared with saphenous-vein coronary bypass grafts, internal-thoracic-artery grafts conferred a survival advantage throughout a 15-year follow-up period. The survival advantage increased with time, suggesting that the initial selection of the conduit was a more important factor in survival than problems appearing long after surgery, such as the progression of coronary disease.

Myocardial infarction in young adults: Angiographic characterization, risk factors and prognosis (coronary artery surgery study registry)

OBJECTIVESnThis study examined the angiographic characteristics, coronary risk factors and prognosis in young men and women with a history of myocardial infarction compared with that in older patients.nnnBACKGROUNDnThere are few data regarding myocardial infarction in young adults. It is undetermined whether the development of myocardial infarction at a young age represents a form of coronary heart disease with an adverse prognosis.nnnMETHODSnOf the 8,839 patients with a history of myocardial infarction in the Coronary Artery Surgery Study (CASS), there were 294 men < or = 35 years old and 210 women < or = 45 years old. Coronary anatomy, baseline characteristics and prognosis were compared in younger and older patients.nnnRESULTSnYoung men and women more often had angiographically normal coronary arteries, nonobstructive disease < 70% stenosis and single-vessel disease than older patients (p < 0.0001). Current smoking was more frequent in young patients (p < 0.0001). Hypertension and diabetes were more frequent in both older men and women, whereas a positive family history of premature coronary disease was significantly more prevalent only in young men. The survival rate at 7 years was improved for young men compared with that in older men (84% vs. 75%, p = 0.0094) and for young women compared with that in older women (90% vs. 77%, p = 0.0004). When multivariate analysis was applied to the data, the survival advantage for young patients remained after adjustment.nnnCONCLUSIONSnYoung patients with a myocardial infarction have a favorable prognosis compared with that in older patients.

Recurrence of angina after coronary artery bypass surgery : predictors and prognosis (CASS Registry)

OBJECTIVESnThis study sought to define the predictors and prognosis of postoperative angina in patients undergoing coronary artery bypass surgery.nnnBACKGROUNDnAngina recurs in the first postoperative year in 20% to 30% of patients after coronary artery bypass surgery. The Coronary Artery Surgery Study Registry provides an opportunity to study the predictors and prognosis of postoperative angina in a large sample.nnnMETHODSnAll patients with isolated coronary artery bypass surgery in the registry were identified, and anginal status was determined on a yearly basis. The influence of angina on mortality, recurrent myocardial infarction and need for reoperation was determined.nnnRESULTSnAngina recurred in the first year in 24% of patients and by the sixth year in 40%. The significant predictors in a multivariate analysis were minimal coronary artery disease, preoperative angina, use of vein grafts only, previous myocardial infarction, incomplete revascularization, female gender, smoking and younger age. In subsequent years important predictors were angina in the first postoperative year, female gender, younger age and incomplete revascularization. The presence of angina in the first postoperative year was associated with more frequent myocardial infarction (p = 0.04) and greater need for reoperation (p = 0.003) but did not affect survival during the 6-year follow-up period.nnnCONCLUSIONSnThese findings show that the predictors of postoperative angina are features that are or could be predicted before bypass surgery. Thus, patients with these features before bypass surgery could be advised that they would be more likely to experience postoperative angina than those without these features. Postoperative angina is associated with an increased risk of late myocardial infarction and reoperation.

Clinical implications of internal mammary artery bypass grafts: the Coronary Artery Surgery Study experience.

From the Coronary Artery Surgery Study Registry, all patients undergoing initial bypass surgery procedures with independent vein grafts were identified. The 950 patients receiving an internal mammary artery bypass graft were compared with the 6027 patients receiving vein graft alone. Improved survival rates with internal mammary artery grafts were noted at hospitals in which these grafts were performed infrequently as well as those in which the internal mammary artery graft was used frequently. The improved survival was noted in patients with normal (p = .004) as well as impaired (p = .004) ventricular function, in men (p = .0001) as well as women (p = .005), in patients over age 65 (p = .01) as well as younger patients (p less than .0001), and in those with (p = .05) or without (p less than .0001) critical stenosis of the left main coronary artery. The internal mammary artery bypass graft was an independent predictor of survival (p = .0004) and reduced the risk of dying by a factor of 0.64. It was concluded that the internal mammary artery graft is the bypass vessel of choice and should not be denied any subgroup.

Ethical issues for invasive cardiologists: Society for cardiovascular angiography and interventions.

In view of the major impact of medical economic forces, rapidly changing technology, and other pressures on invasive cardiologists, the Society for Cardiovascular Angiography and Interventions determined that a statement of the ethical issues confronting the modern invasive cardiologist was needed. The various conflicts presented to the cardiologist in his or her roles as practicing clinician, administrator of the catheterization laboratory, educator, or clinical researcher were reviewed. In all instances, the major concern was determined to be the welfare of the patient no matter how forceful the pressures from various outside force or concerns for personal advancement might be. Catheter Cardiovasc Interv 2004;61:157–162.

Five-year follow-up of microsurgical multiple internal thoracic artery grafts

In a consecutive series of 143 patients requiring multiple coronary artery bypass grafts, 317 of 441 anastomoses (72%) were constructed from internal thoracic arteries. Of these 143 patients, 103 had bilateral, 51 sequential, and 49 free internal thoracic artery grafts. When compared with an earlier series of 494 patients who underwent only one internal thoracic artery anastomosis, the surgical morbidity and mortality were not increased, but, during 5 years of follow-up, the incidences of postoperative angina and myocardial infarction were found to decrease significantly--32.5% versus 10.5% (p < 0.001) and 5.7% versus 1.4% (p < 0.03), respectively. We conclude that, for patients with multivessel disease, multiple internal thoracic artery grafts confer better protection from the clinical manifestations of ischemic heart disease than does one internal thoracic artery graft. The use of high magnification (8 to 12x, surgical microscope) was essential to the success of this method.

Temporary pacemaker use during coronary arteriography

The risk of life-threatening ventricular arrhythmias complicating coronary angiography is reportedly increased in patients in whom temporary righ ventricular pacemakers are used. Placement of the temporary pacing electrode in the right atrium or vena cava during angiography theoretically removes from the vulnerable ventricle a source of mechanically or electrically induced ventricular arrhythmias. This hypothesis was evaluated in 7,648 consecutive patients who underwent cardiac catheterization with selective coronary angiography, including 103 with life-threatening ventricular arrhythmic complications. The prevalence of ventricular arrhythmias was 6.4 times greater in patients with temporary pacemakers than in those without (7% vs 1.1%, respectively, p less than 0.001). Analysis of 369 cardiac catheterizations concurrently using temporary pacemakers revealed a greater than 4-fold decrease in the frequency of ventricular arrhythmias when the pacing electrodes were located in the right atrium or vena cava rather than the right ventricle (2% vs 9%, respectively, p less than 0.01). No significant difference in indications for temporary pacing could be distinguished between the groups based on location of the pacing electrode or occurrence of ventricular arrhythmias. These findings confirm that there is an increased risk of ionic contrast agent-induced ventricular arrhythmias in patients with chronic underlying conduction disturbances undergoing coronary angiography with concurrent right ventricular temporary pacemakers. This risk can be significantly decreased by placing the pacing electrode in the right atrium or vena cava.

Increased Risk of Ventricular Fibrillation Associated with Temporary Pacemaker Use During Coronary Arteriography

Each injection of angiographic contrast dye during coronary arteriography represents a “natural experiment” in which the human ventricular fibrillation threshold is transiently reduced. Few factors, however, have been identified which favor the actual occurrence of ventricular fibrillation in this setting. Of 3906 consecutive patients undergoing selective coronary arteriography with sodium meglumine diatrizoate, 66(1.7 percent) experienced dye‐induced ventricular fibrillation, from which all were successfully defibrillated. Analysis of these cases revealed, unexpectedly, that patients in whom temporary right ventricular pacemakers were employed had an incidence of ventricular fibrillation nearly six times that found in the entire group undergoing arteriography (10 percent vs. 1.7 percent, respectively; P<.001). Those individuals receiving pacemakers were distinguished from other studied patients only by a higher prevalence of conduction abnormalities. Although there is normally a low probability that mechanical stimulation by a pacing catheter can induce ventricular fibrillation, it is postulated that such an occurrence may be more likely after ventricular vulnerability has been increased by contrast dye.

Successful replacement of aortic and mitral valves with ball valve prostheses in a patient with rheumatic heart disease and SC hemoglobinopathy

Abstract We report here the successful prosthetic replacement of cardiac valves in a patient with a severe sickle cell hemoglobinopathy: a 22 year old Negro woman with mitral stenosis, mitral insufficiency, aortic insufficiency and heterozygosity for hemoglobin S and hemoglobin C (hemoglobin SC disease). Clinical severity of her cardiac disease made aortic and mitral valve replacement mandatory, despite lack of adequate precedent for this operation in a patient with severe hemolytic disease and despite the fact that hemoglobin SC erythrocytes are known to be usually susceptible to mechanical trauma. The risk of sickling at operation was diminished by a 70 percent partial exchange transfusion with normal erythrocytes accomplished at the time of cardiac bypass. Red cell fragmentation characteristic of damage by intracardiac prostheses developed and persisted postoperatively, but red cell survival remained unchanged. Cardiac status after 2 1 2 years continues to be markedly improved.