Results of 130 consecutive percutaneous transluminal coronary angioplasty (PTCA) procedures in single and multiple vessel coronary artery disease (CAD)

Over the last 1-year period, we performed 130 consecutive percutaneous transluminal coronary angioplasty (PTCA) procedures in 108 patients, 103 of them were males and 5 females. Their mean age was 50.9 +/- 6.83 years (range 33-70). All of them were symptomatic, manifested by acute infarction in 18 (17%), chronic stable angina in 30 (28%), unstable angina in 5 (5%) and post-myocardial infarction angina in 55 (51%) cases. Among these patients, single-vessel CAD was present in 42 (39%), double-vessel in 37 (34%) and triple-vessel CAD in 11 (10%) patients. Nine patients (8.3%) had total occlusion, and 18 (16.6%) had tandem or bifurcation lesions of target artery. Of the 112 PTCA procedures (excluding those in acute infarction), 53 (47%) were performed on LAD, 29 (26%) on RCA, and 30 (27%) on circumflex artery, with success rates of 86.7%, 83.3% and 82.7% respectively. The overall success rate was 85% (95 of 112). The PTCA was successful in 36 of 42 (85.7%), 32 of 37 (86.5%) and 9 on 11 (82%) patients with single, double and triple-vessel CAD respectively. The mean diameter stenosis reduced from 67.1 +/- 16.54% to 19.9% +/- 10.9%. PTCA was unsuccessful in 17 (15%) due to failure to cross the lesion in 11 (9.7%), failure to dilate in 1 (0.9%) and abrupt reclosure of dilated segment in 5 (4.4%). Four (3.5%) patients underwent CABG. Two patients had redo PTCA owing to restenosis at about 6 months of first PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Subvalvular aneurysm. Two-dimensional echocardiographic features

A rare case of subvalvular aneurysm diagnosed by two-dimensional echocardiography and confirmed at cardiac catheterization is presented.

Streptokinase--biochemistry and clinical application

Plasminogen activation to plasmin is due to enzymatic cleavage of a single peptide bond in the zymogen molecule. Streptokinase is not an enzyme and its activation of plasminogen is indirect. Streptokinase forms stoichiometric complexes with plasmin and plasminogen and these complexes activate plasminogen to plasmin. Streptokinase is species selective in its action.

Ancrod enhances the thrombolytic effect of streptokinase and urokinase

Since thrombi continue to incorporate fibrin during lysis we tested the effect of pretreatment with ancrod, a defibrinating agent from Malaysian pit viper venom, on thrombolysis with urokinase and streptokinase. Thrombi were induced by copper-coils in the carotid arteries of the dogs, weighed after 1 hour and inserted into the femoral arteries of the same animals. They were then exposed for 15 min to iv boluses of streptokinase 10,000 U/kg, urokinase 10,000 U/kg and urokinase 25,000 U/kg with or without pretreatment with ancrod. Ancrod depleted fibrinogen within 5 min and enhanced the lytic effect of streptokinase from 25 +/- 8% to 59 +/- 13% (p less than .05), urokinase 10,000 U/kg from 16 +/- 11% to 66 +/- 18% (p less than .01) and urokinase 25,000 U/kg from 27 +/- 17% to 85 +/- 8% (p less than .001) of the initial thrombus weight. Ancrod itself did not activate plasminogen to plasmin. We conclude that ancrod enhances thrombolysis probably by depleting fibrinogen and preventing new fibrin incorporation into the thrombus during lysis.

Interaction of SK-human plasmin, SK-dog plasmin complexes with alpha 2-antiplasmin and alpha 2-macroglobulin

In patients treated with streptokinase there is a rapid and significant decrease in the level of fibrinogen in the circulation. In dogs given streptokinase there is no such change in circulating fibrinogen. To find an explanation for this species difference in response to streptokinase, the inhibition of SK-human plasmin and SK-dog plasmin by soybean trypsin inhibitor, alpha 2-antiplasmin and alpha2-macroglobulin were compared in this study. Soybean trypsin inhibitor completely blocked the hydrolysis of S-2251 substrate (D-val-L-leu-lys-p-nitroanilide) by SK-dog plasmin and had no effect on SK-human plasmin. Alpha 2-Antiplasmin, the physiologically important regulator of fibrinolysis, inhibited S-2251 hydrolysis by SK-dog plasmin but not the activity of SK-human plasmin. alpha 2-Macroglobulin showed 100% inhibition of proteolytic activity and 50% inhibition of S-2251 activity of SK-dog plasmin, and had no effect on SK-human plasmin. Studies with fresh human and dog plasma also showed that the SK-dog plasmin is rapidly inactivated by the alpha 2-antiplasmin present in the plasma. The inactivation of SK-dog plasmin and not SK-human plasmin by plasma inhibitors explains the differences in the response of dog and humans to the administration of streptokinase.

Kallikrein-like activity of crotalase, a snake venom enzyme that clots fibrinogen

During the amino acid sequence determination of crotalase (EC 3.4.21.30), the thrombin-like enzyme from the venom of Crotalus adamanteus (eastern diamondback rattlesnake), we found that, in addition to the expected structural homology with bovine thrombin (EC 3.4.21.5), there was even greater homology with porcine pancreatic kallikrein (EC 3.4.21.8). In exploring further the similarities between crotalase and kallikrein, several striking observations were made. First, crotalase was rapidly and specifically inhibited by the tripeptide affinity labeling derivative prolylphenylalanylarginine chloromethyl ketone, which is known to be a specific inhibitor of kallikrein. Second, NaDodSO4/acrylamide gel electrophoresis revealed that crotalase cleaves the plasma kallikrein-susceptible bonds in human high molecular weight kininogen, producing an intermediate with procoagulant activity. Crotalase-catalyzed cleavage of high molecular weight kininogen also liberates kinin as evidenced by rat blood pressure bioassay. Finally, crotalase exhibits substrate specificity not only for the thrombin chromogenic substrate S-2238 but also for the kallikrein substrates S-2302 and S-2266. Interestingly, one of the other reactions catalyzed by plasma kallikrein, the activation of plasminogen, was not one of the activities exhibited by crotalase.

Thrombin-like and fibrinolytic enzymes in the venoms from the Gaboon viper (Bitis gabonica), eastern cottonmouth moccasin (Agkistrodon p. piscivorus) and southern copperhead (Agkistrodon c. contortrix) snakes

Crude venom from B. gabonica contained weak fibrinogen clotting activity but no visible fibrinolytic activity, whereas venoms from A. p. piscivorus and A. c. contortrix exhibited fibrinolytic activity (by fibrin plate assay) but no thrombin-like activity. These snake venoms were fractionated on Sephadex G-100 with the following results. Thrombin-like activity in B. gabonica venom was eluted in a single protein peak with a molecular weight of 40,000. Agkistrodon p. piscivorus venom contained a single peak of fibrinolytic activity with a molecular weight of 34,000. Interestingly, venom from A. c. contortrix, which showed no thrombin-like activity in crude venom, contained both thrombin-like and fibrinolytic activities in fractions with molecular weights of 73,000 and 25,000 respectively. No plasminogen activation activity was observed in any of the crude venoms or venom fractions eluted from G-100. In view of the possible clinical potential of these enzymes as defibrinogenating or thrombolytic agents, it will be of great interest to further purify and characterize them.