[Phase variations in the left coronary transstenotic pressure gradient before and after dilatation by percutaneous coronary angioplasty]. / Variations phasiques du gradient de pression transsténotique coronaire gauche avant et après dilatation par angioplastie coronaire percutanée.

The concept of significant coronary stenosis may be approached by studying the effects of the narrowing not in absolute values of pressure and flow but by studying the mode of blood flow across the stenosis. Ten patients with isolated stenosis of the LAD were studied for phasic variations of the transstenotic pressure gradient before and after dilatation. The material used was a ST 3.7 catheter with a 0.12 inch guide. Instantaneous pressure recording throughout the cardiac cycle were obtained using a computer. After dilatation, the area of the stenosis minus the area of transverse section of the dilating catheter increased from 0.5 +/- 0.3 to 2.2 +/- 0.3 mm2, the average gradient between the aorta and the post stenotic LAD decreased from 75 +/- 10 to 12 +/- 8 mmHg, and the ratio between the mean diastolic gradient and mean gradient increased from 75 +/- 7 to 245 +/- 30% (p less than 0.01 for the 3 parameters, paired t test). These results show that the LAD transstenotic pressure gradient is not phasic in severe stenosis. It becomes phasic, only in diastole, after dilatation of the stenosis (slight residual stenosis due to the catheter). This difference may be due to the type of flow, continuous and dependent on the stenosis before dilatation, or phasic dependent on the distal coronary circulation after dilatation. Analysis of the phasic changes of coronary flow may be useful for the evaluation of the severity of left coronary stenosis in the absence of pressure measurements.

[Results of percutaneous valvuloplasty in calcified aortic stenosis in the adult]. / Résultats de la valvuloplastie percutanée dans le rétrécissement aortique calcifié de l'adulte.

Aortic valvuloplasty by percutaneous valve dilatation was attempted in 52 patients aged from 60 to 88 years, 20 of whom were in functional stage IV with pulmonary oedema at the time of the procedure. Forty-seven stenoses could be dilated, with haemodynamic success (50 p. 100 increase of aortic valve area) in 44 patients. Among these 44 patients, 3 had to be operated upon because of persistent functional symptoms and 3 died during their stay in hospital (2 as a result of the procedure or the cardiopathy, 1 of heart failure unrelated to the aortic stenosis or the dilatation). The primary success rate therefore was 38/52 attempts, or 72.9 p. 100. The first 11 patients regarded as initial success could be followed up for at least 6 months: functional improvement with moderate myocardial alteration persisted in 9 of them, but Doppler examination in one showed restenosis. Two patients with severe myocardial dysfunction relapsed into cardiac failure; restenosis could be dilated in one of them. Percutaneous aortic valvuloplasty is an effective treatment of calcified aortic stenosis in elderly people who remain improved for at least 6 months when myocardial lesions are mild or moderate. The procedure incompletely reduces the aortic stenosis, which may account for the left of improvement in left ventricular function in patients with severe myocardial damage prior to dilatation. For this subgroup of patients, the choice lies between percutaneous valvuloplasty, which avoids surgery, and surgery which ensures a more complete haemodynamic result in the valve.