Shahin Keramati

Elevated plasma fibrinogen and diabetes mellitus are associated with lower inhibition of platelet reactivity with clopidogrel.

OBJECTIVES The goal of this study was to identify factors associated with lower platelet inhibition (PI) with clopidogrel in subjects with cardiovascular disease (CVD). BACKGROUND A heterogeneous platelet reactivity response to clopidogrel exists, and the clinical or biochemical predictors of suboptimal PI with clopidogrel remain unclear. METHODS This study prospectively enrolled subjects with CVD requiring treatment with clopidogrel (75 mg daily for > or =7 days or 600-mg bolus > or =24 h before recruitment). A bedside rapid platelet function assay (VerifyNow, Acccumetrics, San Diego, California) to measure maximal and clopidogrel-mediated platelet reactivity was utilized, and factors associated with lower PI were identified. RESULTS A heterogeneous, normally distributed PI (mean 40.8 +/- 26.2%) response to clopidogrel was observed in 157 subjects (age 67.2 +/- 12.2 years; 59.9% men). Multiple variable analysis of clinical and biochemical factors known to affect platelet reactivity revealed lower PI in patients with an elevated plasma fibrinogen level (> or =375 mg/dl), diabetes mellitus, and increased body mass index (BMI) (> or =25 kg/m(2)). On testing for interaction, elevated fibrinogen level was associated with diabetic status, resulting in lower PI in diabetic patients (23.9 +/- 3.9% vs. 45.1 +/- 4.5%, p < 0.001), but not nondiabetic patients (44.7 +/- 4.4% vs. 46.3 +/- 4.8%, p = 0.244). Increased BMI remained independently associated with lower PI after clopidogrel therapy regardless of diabetic status or fibrinogen level (36.8 +/- 9.0% vs. 49.0 +/- 7.0%, p < 0.001). CONCLUSIONS Elevated plasma fibrinogen (> or =375 mg/dl) in the presence of diabetes mellitus and increased BMI (> or =25 kg/m(2)) are associated with lower PI with clopidogrel in patients with CVD.

Renal Frame Count and Renal Blush Grade: Quantitative Measures That Predict the Success of Renal Stenting in Hypertensive Patients With Renal Artery Stenosis

OBJECTIVES This study sought to identify angiographic parameters of favorable clinical response to renal artery stenting. BACKGROUND Stenting improves blood pressure (BP) control in patients with renal artery stenosis (RAS), but markers predicting a favorable clinical response are limited. METHODS Renal perfusion was quantified in hypertensive patients (BP >or=140/90 mm Hg) without RAS by determining renal frame count (RFC) (angiographic frames [30 frames/s] for contrast to reach distal renal parenchyma after initial renal artery opacification) and renal blush grade (RBG) (0: none, 1: minimal, 2: normal, 3: hyperemic parenchymal blush). It was hypothesized that stenting unilateral RAS in hypertensive patients would result in decreased RFC and increased RBG, which might predict BP reduction. RESULTS The RFC in 17 consecutive hypertensive patients without RAS (control group) (64.4 +/- 14.2 years, 12 male, 22 kidneys) was 20.1 +/- 5.4, whereas RBG was 2.33 +/- 0.66. In 24 consecutive hypertensive patients with unilateral RAS (study group) (72.7 +/- 11.3 years, 8 male), reduced RFC (26.6 +/- 9.1 to 21.4 +/- 6.7, p < 0.001) and increased RBG (1.63 +/- 0.71 to 2.13 +/- 0.85, p = 0.03) were observed after renal stenting. At 6 months, reduced BP (systolic BP 150.6 +/- 15.6 mm Hg to 128.6 +/- 15.5 mm Hg, p < 0.001; diastolic BP 77.2 +/- 15.6 mm Hg to 68.3 +/- 10.4 mm Hg, p = 0.022) without change in number of hypertensive medications was observed. Clinical responders (systolic BP reduction >15 mm Hg) had a greater decrease in RFC (7.7 +/- 4.6 vs. 1.7 +/- 5.1, p = 0.009) and 78.6% of patients with >4 RFC decrease were responders (p = 0.024). CONCLUSIONS This study shows that quantitative indices of renal perfusion (RFC and RBG) are impaired in patients with RAS and improve after stenting, and that RFC reduction is associated with BP reduction.

Infrahepatic Interruption of the Inferior Vena Cava with Azygos Continuation: A Potential Mimicker of Aortic Pathology

Infrahepatic interruption of the inferior vena cava (IVC) with azygos or hemiazygos continuation is a rare finding. In this anatomic entity, the intrahepatic segment of the IVC is absent, and the hepatic veins empty directly into the right atrium. Venous blood flow from the lower body is directed from the IVC into the azygos system at the level of the renal veins, with resultant dilation of the azygos and/or hemiazygos veins. Because these enlarged vessels lie parallel to the descending thoracic aorta, they may be mistaken for aortic pathology (dissection, aneurysm, or rupture) during transesophageal echocardiography (TEE). We describe a case of azygos continuation of the IVC initially misdiagnosed by TEE as partial aortic rupture. Repeat TEE with intravenous agitated saline injection correctly identified the condition, and the echocardiographic features are described.