Improvement of coronary microvascular function after Angiotensin receptor blocker treatment with irbesartan in patients with systemic hypertension.

Patients with hypertension exhibit changes in vessel conductance and resistance. The aim of this study was to evaluate the effect of the angiotensin receptor blocker irbesartan on coronary microvascular function. Thirty-six hypertensive patients without coronary artery or systemic disease were examined. Coronary flow velocity reserve (CFR) was measured using transthoracic Doppler echocardiography in 18 men (54±9 years) before and after 3 months of treatment with 600 mg/d of irbesartan and in 18 controls (55±11 years). Carotid intima-media thickness (IMT) was evaluated with high-resolution echocardiography. Baseline CFR did not differ between groups. CFR significantly improved in the irbesartan group (from 2.87±.42 to 3.78±.32; P<.001), but remained unchanged in controls (from 2.94±.61 to 3.06±.72; P=not significant). CFR improved with treatment independent of associated risk factors. BP decreased from 150±18 mm Hg to 129±25 mm Hg (P<.001) during treatment, whereas IMT and left ventricular mass index showed no significant differences at the end of the follow-up period in both groups. Three-month irbesartan treatment significantly increased CFR in patients with hypertension. This improvement is attributed to blockade of the renin-angiotensin system. Coronary microvascular function was shown to improve independent of hypertrophy regression. Patients with lower baseline CFR tended to show a more pronounced CFR response.

Coronary artery flow reserve in diabetics with erectile dysfunction using sildenafil.

BACKGROUND: Diabetics with erectile dysfunction have a high prevalence of microvascular disturbance of the coronary circuit as measured by coronary flow reserve (CFR). PURPOSE: We aimed to evaluate the effects of the phosphodiesterase 5 inhibitor sildenafil on CFR in diabetics with erectile dysfunction. METHODS: Diabetics seeking diabetes refinement therapy were screened for vascular or neurogenic erectile dysfunction which was confirmed in 43 patients. No ischemic ECG changes were found in any of the ECG stress tests at the 100 W level. Cardiologic examinations raised suspicion of coronary artery disease in 16 patients; coronary angiography confirmed severe coronary artery lesions in 12, who were excluded from further analysis. CFR measurements were not possible in 10 participants. The 21 diabetics eligible for CFR measurements aged 60 years (50-69) had known diabetes for 11 years (3-30) and a BMI of 27 kg/m2 (24-36). CFR of the left anterior descending artery was assessed at baseline and 1 hour after 50 mg sildenafil, using transthoracic Doppler echocardiography. RESULTS: Baseline CFR was at the lower level of the normal range (median 245%, range 210-490%). After sildenafil administration, CFR decreased insignificantly (DeltaCFR -10%, p = 0.3). Patients with a BMI > 25 kg/m2 and left ventricular hypertrophy exhibited the highest reduction of CFR after sildenafil. No decrease of CFR below 200 % was observed. Systemic blood pressure dropped from 130/80 mmHg to 120/72 mmHg (p < 0.002). CONCLUSIONS: Diabetics with erectile dysfunction exhibit a CFR in the lower normal range indicating severe microvascular disturbance. Sildenafil did not alter CFR in those patients. A high prevalence of severe coronary macroangiopathy was identified in asymptomatic diabetic patients screened for contraindications for sildenafil.

Comparison of transthoracic Doppler echocardiography to intracoronary Doppler guidewire measurements for assessment of coronary flow reserve in the left anterior descending artery for detection of restenosis after coronary angioplasty.

Transthoracic Doppler echocardiography (TDE) has been described as a feasible and accurate technique to noninvasively assess coronary flow reserve (CFR) in the left anterior descending artery (LAD). This study was designed to evaluate whether serial assessment of CFR in the LAD using TDE allows detection of restenosis after previously performed angioplasty. Thirty-three consecutive patients with single-vessel coronary artery disease of the LAD scheduled for angioplasty underwent assessment of coronary flow velocity at rest and during adenosine-induced hyperemia in the distal LAD using high-frequency TDE. CFR was calculated as the ratio of hyperemic to basal systolic/diastolic mean velocity. Investigations were performed before and immediately after angioplasty, and at the time of control angiography after 3 months. CFR results by TDE were compared with intracoronary Doppler guide wire measurements. Adequate pulse-wave Doppler signals to measure CFR were obtained in 30 patients (91%) using TDE. There was close correlation between echocardiographically and intracoronary derived CFR results (r = 0.80, 0.79, and 0.87 before angioplasty, early after, and at 3- month control angiography, respectively; p <0.001). Using a cut-off value of CFR < or =2.0 to identify significant coronary artery disease, TDE detected LAD restenosis with a sensitivity of 89% and specificity of 90%. Thus, high-frequency TDE is a feasible technique to noninvasively assess CFR in the LAD with results closely corresponding to invasive measurements. Defining a cut-off value of CFR < or =2.0, the technique has the potential to reliably detect LAD stenosis after coronary intervention.

Transthoracic echocardiographic visualization of coronary artery blood flow and assessment of coronary flow reserve in the right coronary artery: a first report of 3 patients.

Assessment of coronary flow reserve (CFR) has proven to be an important diagnostic tool providing useful clinical and physiologic information about coronary artery function. In several studies, the transthoracic echocardiographic assessment of CFR, defined as a ratio of hyperemic to basal coronary flow velocity, was validated in the left anterior descending artery. But so far, the visualization of coronary flow and the measurement of CFR were limited to the mid and distal portion of the left anterior descending artery. Introduction of a modified 2-chamber view enables the recording of coronary blood flow and the assessment of CFR in the posterior descending branch of the right coronary artery in selected patients. This report of 3 cases describes for the first time a method to visualize and measure coronary blood flow in the distal right coronary artery by precordial Doppler echocardiography.