[Changes in PTCA. A model of ischemia in humans].

Percutaneous transluminal coronary angioplasty provides the opportunity to study ischemic alterations in the setting of acute transient coronary occlusions in man. In 124 patients changes in hemodynamics, global and regional left ventricular function, collateral flow and mitral valve incompetence, alterations in the concentrations of atrial natriuretic peptide, renin and aldosterone concentrations as well as metabolic changes were studied. In 39 patients with single vessel disease presenting with isolated stenosis in the left anterior descending artery (LAD), but normal global as well as regional left ventricular function hemodynamic and ventriculographic abnormalities were found to be present during intraluminal occlusion for 60 seconds. The mean heart rate increased from 76.3 +/- 15.8 to 80.4 +/- 14.9 beats/min (p less than 0.01) and the mean end diastolic volume index (EDVI) increased from 92.8 +/- 17.1 to 104.6 +/- 17.1 ml/m2 (p less than 0.001). The end systolic volume index (ESVI) also increased from 27.5 +/- 11.3 to 48.2 +/- 12.1 ml/m2 (p less than 0.001). By contrast, mean global left ventricular ejection fraction showed a highly significant reduction from 70.7 +/- 8.8 to 53.8 +/- 7.9% (p less than 0.001). This was paralleled by a reduction in circumferential fibre shortening velocity (VCF) from 1.44 +/- 0.48 to 0.81 +/- 0.31 L/s during LAD occlusion (p less than 0.001). Mean end diastolic left ventricular pressure (EDP) rose significantly from 17.0 +/- 6.8 to 30.1 +/- 9.0 mm Hg (p less than 0.001). In the left ventricular segments supplied by the LAD there was a significant drop in regional shortening. Compensatory increase of regional wall motion in the segments supplied by the right coronary artery (RCA) or circumflex artery (ACX) could not be documented. In the group as a whole the end systolic pressure-volume curves were found to be shifted to the right and the end diastolic pressure-volume curves were elevated, indicating a decrease of contractility and an increase of chamber stiffness. During four consecutive balloon inflations 60 patients showed a significant (p less than 0.001) reduction in peak dp/dtmax and peak dp/dtmin values within the first 30 seconds after coronary artery occlusion and a highly significant (p less than 0.001) increase in left ventricular end diastolic pressures. These changes proved to be reproducible and were found to be almost identical in the four consecutive inflation cycles. The effects of reperfusion were also studied with reperfusion times of 1 min in 15 patients, 3 min in 20 patients and 5 min in 25 patients.4+ balloon inflation.(ABSTRACT TRUNCATED AT 400 WORDS)