- Email: [email protected]
Plasma homocysteine levels and mortality in patients with coronary artery disease
LITERATURE REVIEW
tivity during adenosine infusion and after reperfusion. Thallium scanning identified 65 of 68 patients with angiographically confirmed coronary stenoses (sensitivity, 96%) and was 61% specific. Falsepositive results were attributed to native stenoses beyond a patent graft or to fixed perfusion defects.
Tousoulis D, Tentolouris C, Crake T, et al: Basal and flow-mediated nitric oxide production by atheromatous coronary arteries. J Am Coil Cardio129:12561262, 1997 Nitric oxide (NO) mediates vasodilation of normal coronary arteries. Its effects in atherosclerotic coronary arteries was investigated in 16 patients with positive stress test and in 6 normal patients using atrial pacing and NG-monomethyl-L-arginine infusion (NO syntheLase inhibitor). Coronary blood flow was measured using a 20-MHz endovascular Doppler, and coronary artery lumen diameter was measured angiographically. An increase in lumen diameter occurred with atrial pacing, which was not demonstrated during pacing and infusion of LNMMA. This occurred in both normal and diseased coronary arteries alike. The increase in coronary artery velocity seen with pacing was less during LNMMA infusion, but was only significant in the patients with normal coronary arteries. This study confirms that epicardial coronary artery vasodilation in response to atrial pacing is NO-dependent.
Konecky N, Malinow R, Tunick PA, et al: Correlation between plasma homocysteine and aortic atherosclerosis. Am Heart J 133:534-540, 1997 Patients referred for transesophageal echocardiography (]'EE) were studied (n = 156). Plasma samples were obtained for homocysteine, vitamins B12, B6, and folic acid levels. During TEE, plaque areas were measured in the distal aortic arch, proximal descending aorta, and the distal descending aorta, and were summed to obtain the atherosclerosis degree for each patient. Univariate analyses indicated thal homocysteine level, age, male sex, smoking, vascular disease, coronary disease, and low B6 levels significantly predicted a high degree of at!)erosclerosis. In multivariate analyses, homocysteine level was an independent predictor of atherosclerosis and added to the significance of the model for predicting atherosclerosis.
Nygard O, Nordrehaug JE, Refsum H, et all Plasma homocysteine levels and mortality in patients with coronary artery disease. N Engl J Med 337:230-236, 1997 During a 1-year period, patients referred for coronary angiography were prospectively studied; 587 patients with coronary artery disease (CAD) were evaluated using patient history, results oF coronary angiography, plasma levels of lipids, homocysteine, vitamins B6 and B 12, and 5-year follow-up for mortality. Increased plasma ho~aocysteine levels were statistically associated with age, prior myocardial infarction, ejection fraction less than 0.5, and hypertension. There was a strong graded dose-response relation between higher plasma homocysteine levels and mortality, with a steeper mortality slope a,: homocysteine levels above 15 wnol/L. Although not proof of a causal relation, efforts to reduce homocysteine levels may help to reduce mortality in patients with CAD.
The global use of strategies to open occluded coronary arteries in acute coronary syndromes IGUSTO IIb angioplasty substudy investigators). A clinical trial comparing primary coronary angioplasty with tissue
'~21
plasminogen activator for acute myocardial infarction. N Engl J Med 336:1621-1628, 1997 In this mnlticenter randomized GUSTO trial (57 hospitals, nine countries), primary angioplasty was compared with accelerated thrombolytic therapy (tissue plasminogen activator) for patients presenting with chest pain and electrocardiogram (ECG) evidence of infarction. At the 30-day follow-up, the aggregate occurrence of death, reinfarction, o1 disabling stroke was significantly lower in the angioplasty group than the thrombolysis group (9.6% v 13.7%, p = 0.033). However, 6 months after randomization, no differences in adverse outcome were present. Within the angioplasty group, randomization to anticoagulation with heparln or hirudin revealed no differences between the groups with respect to adverse outcomes or bleeding. Angioplasty seems to offer short-term advantages; however, when instituted rapidly, both strategies offer excellent reperfusion results.
Postoperative Outcome
Meschengieser SS, Fondevila CG, Frontroth J, et al: Low-intensity oral anticoagulation plus low-dose aspirin versus high-intensity oral anticoagulation alone: A randomized trial in patients with mechanical prosthetic heart valves. J Thorac Cardiovasc Surg 113:910916, 1997 After placement of a mechanical valve prosthesis, 503 patients were randomly assigned to receive either oral anticoagulatinn (internalized normalized ratio [INR] 2.5 to 3.5) plus aspirin (100 mg/day), or oral anticoagulation alone (INR 3.5 to 4.5). Median follow-up was for 23 months during which patients were monitored for thromboembolic events and major hemorrhage. The incidence of embolism was 2.7% for the combined therapy group and 2.8% for monotherapy group. The occurrence of major bleeding was 2.32% for the combined therapy group and 4.49% in the monotherapy group, which represents a 52% reduction in bleeding risk. Further study is needed to identify particnlar subgroups of patients who may benefit from combined therapy.
Katz NM, Chase G: Risks of cardiac operations for elderly patients: Reduction of the age factor. Ann Thorac Surg 63:1309-1314, 1997 In review of a five year cardiac surgery database, the authors evaluated 853 surgeries and stratified patients into two groups: younger than 70 years of age and older than 70 years of age. Thirty-day mortality, length of stay, and hospital charges were compared. There was no difference in mortality between the two groups (1.8% in both groups), even when adjusted for risk factors such as poor ventricnlar function, increased creatinine, emergency operation, or valvular operation. Length of stay was longer for the older group of patients although both groups experienced a 3.5 to 5 day decrease in length of stay over the 5-year period. Hospital charge rates were 1.13 times higher in the elderly group.
Blanche C, Matloff JM, Denton TA, et al: Cardiac operations in patients 90 years of age and older. Ann Thorac Surg 63:1685-1690, 1997 This was a retrospective review of 30 consecutive nonagenarians, with a mean age 92 _+ 1.8 years. Morbidity, 30-day mortality, dh:ect costs, indirect costs, and 24-month follow-up status were assessed. All cases were either urgent or emergent. There were no intraoperative deaths, and the 30-day mortality was 10%. Mean length of stay was 13.5 days, with a range 5 to 69 days. Complications included tacharrhyth-
tivity during adenosine infusion and after reperfusion. Thallium scanning identified 65 of 68 patients with angiographically confirmed coronary stenoses (sensitivity, 96%) and was 61% specific. Falsepositive results were attributed to native stenoses beyond a patent graft or to fixed perfusion defects.
Tousoulis D, Tentolouris C, Crake T, et al: Basal and flow-mediated nitric oxide production by atheromatous coronary arteries. J Am Coil Cardio129:12561262, 1997 Nitric oxide (NO) mediates vasodilation of normal coronary arteries. Its effects in atherosclerotic coronary arteries was investigated in 16 patients with positive stress test and in 6 normal patients using atrial pacing and NG-monomethyl-L-arginine infusion (NO syntheLase inhibitor). Coronary blood flow was measured using a 20-MHz endovascular Doppler, and coronary artery lumen diameter was measured angiographically. An increase in lumen diameter occurred with atrial pacing, which was not demonstrated during pacing and infusion of LNMMA. This occurred in both normal and diseased coronary arteries alike. The increase in coronary artery velocity seen with pacing was less during LNMMA infusion, but was only significant in the patients with normal coronary arteries. This study confirms that epicardial coronary artery vasodilation in response to atrial pacing is NO-dependent.
Konecky N, Malinow R, Tunick PA, et al: Correlation between plasma homocysteine and aortic atherosclerosis. Am Heart J 133:534-540, 1997 Patients referred for transesophageal echocardiography (]'EE) were studied (n = 156). Plasma samples were obtained for homocysteine, vitamins B12, B6, and folic acid levels. During TEE, plaque areas were measured in the distal aortic arch, proximal descending aorta, and the distal descending aorta, and were summed to obtain the atherosclerosis degree for each patient. Univariate analyses indicated thal homocysteine level, age, male sex, smoking, vascular disease, coronary disease, and low B6 levels significantly predicted a high degree of at!)erosclerosis. In multivariate analyses, homocysteine level was an independent predictor of atherosclerosis and added to the significance of the model for predicting atherosclerosis.
Nygard O, Nordrehaug JE, Refsum H, et all Plasma homocysteine levels and mortality in patients with coronary artery disease. N Engl J Med 337:230-236, 1997 During a 1-year period, patients referred for coronary angiography were prospectively studied; 587 patients with coronary artery disease (CAD) were evaluated using patient history, results oF coronary angiography, plasma levels of lipids, homocysteine, vitamins B6 and B 12, and 5-year follow-up for mortality. Increased plasma ho~aocysteine levels were statistically associated with age, prior myocardial infarction, ejection fraction less than 0.5, and hypertension. There was a strong graded dose-response relation between higher plasma homocysteine levels and mortality, with a steeper mortality slope a,: homocysteine levels above 15 wnol/L. Although not proof of a causal relation, efforts to reduce homocysteine levels may help to reduce mortality in patients with CAD.
The global use of strategies to open occluded coronary arteries in acute coronary syndromes IGUSTO IIb angioplasty substudy investigators). A clinical trial comparing primary coronary angioplasty with tissue
'~21
plasminogen activator for acute myocardial infarction. N Engl J Med 336:1621-1628, 1997 In this mnlticenter randomized GUSTO trial (57 hospitals, nine countries), primary angioplasty was compared with accelerated thrombolytic therapy (tissue plasminogen activator) for patients presenting with chest pain and electrocardiogram (ECG) evidence of infarction. At the 30-day follow-up, the aggregate occurrence of death, reinfarction, o1 disabling stroke was significantly lower in the angioplasty group than the thrombolysis group (9.6% v 13.7%, p = 0.033). However, 6 months after randomization, no differences in adverse outcome were present. Within the angioplasty group, randomization to anticoagulation with heparln or hirudin revealed no differences between the groups with respect to adverse outcomes or bleeding. Angioplasty seems to offer short-term advantages; however, when instituted rapidly, both strategies offer excellent reperfusion results.
Postoperative Outcome
Meschengieser SS, Fondevila CG, Frontroth J, et al: Low-intensity oral anticoagulation plus low-dose aspirin versus high-intensity oral anticoagulation alone: A randomized trial in patients with mechanical prosthetic heart valves. J Thorac Cardiovasc Surg 113:910916, 1997 After placement of a mechanical valve prosthesis, 503 patients were randomly assigned to receive either oral anticoagulatinn (internalized normalized ratio [INR] 2.5 to 3.5) plus aspirin (100 mg/day), or oral anticoagulation alone (INR 3.5 to 4.5). Median follow-up was for 23 months during which patients were monitored for thromboembolic events and major hemorrhage. The incidence of embolism was 2.7% for the combined therapy group and 2.8% for monotherapy group. The occurrence of major bleeding was 2.32% for the combined therapy group and 4.49% in the monotherapy group, which represents a 52% reduction in bleeding risk. Further study is needed to identify particnlar subgroups of patients who may benefit from combined therapy.
Katz NM, Chase G: Risks of cardiac operations for elderly patients: Reduction of the age factor. Ann Thorac Surg 63:1309-1314, 1997 In review of a five year cardiac surgery database, the authors evaluated 853 surgeries and stratified patients into two groups: younger than 70 years of age and older than 70 years of age. Thirty-day mortality, length of stay, and hospital charges were compared. There was no difference in mortality between the two groups (1.8% in both groups), even when adjusted for risk factors such as poor ventricnlar function, increased creatinine, emergency operation, or valvular operation. Length of stay was longer for the older group of patients although both groups experienced a 3.5 to 5 day decrease in length of stay over the 5-year period. Hospital charge rates were 1.13 times higher in the elderly group.
Blanche C, Matloff JM, Denton TA, et al: Cardiac operations in patients 90 years of age and older. Ann Thorac Surg 63:1685-1690, 1997 This was a retrospective review of 30 consecutive nonagenarians, with a mean age 92 _+ 1.8 years. Morbidity, 30-day mortality, dh:ect costs, indirect costs, and 24-month follow-up status were assessed. All cases were either urgent or emergent. There were no intraoperative deaths, and the 30-day mortality was 10%. Mean length of stay was 13.5 days, with a range 5 to 69 days. Complications included tacharrhyth-