Analytical expression of effective afterload in aortic and mitral regurgitation.

Effective arterial elastance (Ea) is the coupling parameter between the left ventricle and peripheral circulation in normal subjects. If left ventricular end systolic pressure (Pes), contractility (Es) and Ea are known, left ventricular end diastolic volume (LVEDV) and ejection fraction of the ventricle are completely determined. The aim of this study was to give an analytical expression for Ea in patients with mitral and aortic regurgitation, and predict both LVEDV and the effect of vasodilator therapy on LVEDV. Twenty-three subjects with atypical chest pain, 15 patients with mitral insufficiency and 11 with aortic insufficiency underwent diagnostic cardiac catheterization, coronary angiography, and left ventricular cineangiography, which was analyzed quantitatively. Ea was 2.05 +/- 0.63 in normal subjects, while it was 1.28 +/- 0.71 and 1.57 +/- 0.87 in patients with mitral and aortic insufficiency, respectively. All these groups differed with ANOVA test (p = 0.0031). We tested the ability of the analytical expressions for Ea in normal subjects, and patients with mitral insufficiency or aortic insufficiency to predict measured Ea and LVEDV. Ea and LVEDV were predicted rather accurately in every case (p < 0.0001). We used published data to test the effect of resistance modulation on LVEDV. Predicted and measured LVEDV were linearly correlated both in aortic (p < 0.0001) and mitral insufficiency (p = 0.027). Moreover, in some cases a left ventricular enlargement after vasodilator therapy could be anticipated because of an unbalanced decrease in resistance and heart rate. Ea seems to be the coupling parameter between the left ventricle and the peripheral circulation not only in normal subjects, but also in patients with mitral or aortic regurgitation; its measurement before administering vasodilating drugs may be useful in order to predict the effects on LVEDV, and achieve an optimal ventriculoarterial coupling.

[Rotational atherectomy and PTCA in complex coronary lesions (B2 and C): the immediate and long-term results]. / Aterectomia rotazionale e PTCA in lesioni coronariche complesse (B2 e C): risultati immediati e a distanza.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) in complex coronary lesions (type B2 and C of the modified AHA/ACC classification) presents a lower primary success rate and higher risk of dissection than type A and B1 lesions. An alternative approach to this lesions is coronary rotational ablation (Rotablator, Heart Technology) with complementary PTCA using low inflation pressures ("facilitated angioplasty"). MATERIALS AND METHODS: Twenty-six type B2 and C lesions in 24 patients (pts) (8 female, 16 male, age 37-80 years) were treated with coronary rotational ablation and complementary PTCA between January 1993 and December 1994 (4.7% of all interventional coronary procedures performed in this period in our laboratory). Eleven pts had stable effort angina and 13 pts had unstable, class IB, IIB, and IIC, angina. The treated vessel was the LAD in 15 cases, CX in 5, RCA in 5, and an intermediate branch in one case. Coronary rotational ablation was proposed because of the presence of two or more risk factors for uneffective or complicated PTCA: eccentricity, calcified lesions, bifurcation stenosis, lesion length > 10 mm, severe stenosis (90-99%), ostial location and bend location (45-60 degrees). No lesion showed coronary thrombus, considered as absolute contraindication to coronary rotational ablation. We used small burrs (burr/artery ratio < 0.75), and complementary PTCA was performed using low inflation pressure (< 8 atm) and long balloons for long lesions (> 10 mm) in order to minimize the risk of dissection. RESULTS: Coronary rotational ablation was successfully performed in all but two cases (24/26; 92.3%), with a reduction of the stenosis from 88 +/- 9% to 45 +/- 10% (range 30-60%). In two pts (7.7%) the procedure was complicated by acute occlusion: both pts underwent effective salvage PTCA with 30% residual stenosis. Small type A and B dissections occurred in 4/26 cases (15.4%). All but one lesions complicated by acute occlusion or dissection following coronary rotational ablation were not or only slightly calcified. Complementary PTCA was performed in all but two pts who already presented 30% residual stenosis after rotational ablation. A further reduction of stenosis to 20 +/- 9% (range 5-30%) was achieved. After complementary PTCA four pts (15.4%) developed type A and B dissections; in one of these a Palmaz-Schatz stent was implanted, whereas the remaining three pts presented a residual stenosis below 30% and no further procedures were undertaken. Overall success rate of rotational atherectomy plus salvage or complementary PTCA or stenting was 100%, and no major complications (Q-wave myocardial infarction, emergency bypass surgery or death) occurred. Three pts showed delayed coronary run-off (slow reflow) after rotational ablation, and two of these released a small amount of cardiac specific enzymes (CK MB) without ECG changes and wall motion alteration on echocardiographic examination. Clinical restenosis, defined as recurrent angina and/or positive exercise stress test, developed in 45.8% (11 pts); in all these pts restenosis was angiographically evidenced (75-99%). CONCLUSIONS: Our experience suggests that coronary rotational ablation along with complementary PTCA using low inflation pressure and long balloons is safe and effective in type B2 and C lesions if calcifications are present; however, restenosis rate remains high.

Simulation of chronic mitral regurgitation.

In mitral regurgitation the left ventricle enlarges in order to increase its stroke volume because of the regurgitation through the mitral valve. The amount of this volume increase, and of the consequent increase in left ventricular mass, its dependent upon the amount of the regurgitant volume, but many other factors come into play, such as left ventricular pumping capability (contractility), the level of peripheral pressure, resistance and compliance of the arterial tree. The aim of this study is to predict the final left ventricular volumes and mass given the amount of mitral regurgitation. The predicted results are compared with actual data in real patients. In most cases prediction is fairly good; some discrepancies can be interpreted as an index of advanced decompensation.