Association between lipoprotein(a) and progression of coronary artery disease in middle-aged men.

The association between lipoprotein(a) (Lp[a]) and progression of coronary artery disease (CAD) compared with other serum lipids was evaluated in 104 patients with angiographically proven coronary atherosclerosis. Patients were randomized to either an intervention or a control group. The 12-month intervention program consisted of a low-fat diet and daily physical exercise. Patients in the control group received "usual care" by their private physician. Eighty-three patients (36 in the intervention and 47 in the control group) underwent repeat angiography after 1 year. Angiographically documented net regression was seen in 13 patients (8 in the intervention and 5 in the control group), no change was seen in 40 patients (21 in the intervention and 19 in the control group) and progression was noted in 30 patients (7 in the intervention and 23 in the control group). No correlation could be shown between Lp(a) and angiographically documented progression of the disease. In a multivariate analysis including metabolic variables, group assignment, age and smoking habits, only assignment to the intervention group (p = 0.0075) and a decrease in total cholesterol (p = 0.0167) were independently associated with the course of the disease. Patients with or without previous myocardial infarction (70 vs 34) did not differ in Lp(a) levels (median 9.15 vs 14.25 mg/dl). Patients with Lp(a) > 25 mg/dl were younger than patients with Lp(a) < or = 25 mg/dl (52 vs 55 years; p < 0.03), indicating a connection between Lp(a) and the development of premature CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-invasive assessment of perioperative myocardial cell damage by circulating cardiac troponin T.

Troponin T is a unique cardiac antigen which is continuously released from infarcting myocardium. Its cardiospecificity as a marker protein might be particularly useful in assessing myocardial cell damage in patients undergoing cardiac surgery. Therefore, circulating troponin T was measured in serial blood samples from 56 patients undergoing cardiac surgery and in two control groups--22 patients undergoing minor orthopaedic surgery and 12 patients undergoing lung surgery by median sternotomy. In both control groups no troponin T could be detected, whereas activities of creatine kinase were raised in all 12 lung surgery controls and activities of the MB isoenzyme were raised in five of the 12 patients in the lung surgery group and in four of the 22 patients in the orthopaedic surgery group, respectively. All the patients undergoing coronary artery bypass grafting (n = 47) and cardiac surgery for other reasons (n = 9) had detectable concentrations of troponin T. Five patients had perioperative myocardial infarction detected as new Q waves and R wave reductions. In these five patients troponin T release persisted and serum concentrations (5.5-23 micrograms/l) reached a peak on the fourth postoperative day. In the 51 patients without perioperative myocardial infarction serum concentrations and the release kinetics of troponin T depended on the duration of cardiac arrest. In patients in whom aortic cross clamping was short troponin T increased slightly on the first postoperative days; in patients with longer periods of aortic cross clamping troponin T concentrations were higher and remained so beyond the fifth postoperative day. In patients with non-specific changes on the electrocardiogram troponin T concentrations were significantly higher on days 1 and 4 after operation than in patients with normal postoperative electrocardiograms(11.2 (5) and 4.5 (2.6) v 8.2 (3.4) and 2.9 (1.6) 1microg/l). Serum concentrations of troponin T showed some myocardial cell damage in every patient undergoing cardiac surgery. The persistent increases that were more common in patients with longer periods of cardiac arrest must have been caused by damage to the contractile apparatus. These results suggest that perioperative myocardial cell necrosis may be more common than indicated by changes of the QRS complex on the electrocardiogram.