Citations

The non‐invasive evaluation of prosthetic valve function is challenging. The effects of flow rate, valvular geometry, leaflet motion, and pressure recovery all impact the Doppler assessment of prosthetic performance. Differentiating prosthesis obstruction from pressure recovery in patients who are found to have high Doppler velocities across an aortic valve prosthesis is critical in order to direct appropriate management. In this manuscript, we present two cases of patients with aortic valve prosthesis with high Doppler velocities and review the pathophysiology and evaluation of prosthesis function. © 2014 Wiley Periodicals, Inc.

Background— Low-gradient severe aortic stenosis with preserved ejection fraction is an increasingly recognized entity, and symptomatic patients may benefit from aortic valve replacement. However, systemic hypertension frequently coexists with low-gradient severe aortic stenosis, which itself may cause elevated left ventricular (LV) filling pressures with resultant symptoms of dyspnea. Methods and Results— Symptomatic patients with hypertension (aortic systolic pressure >140 mm Hg) and low-gradient (mean gradient <40 mm Hg) severe aortic stenosis (aortic valve area <1 cm 2 ) with preserved ejection fraction (ejection fraction >50%) who underwent invasive hemodynamic catheterization of the left and right sides of the heart received infusion of intravenous sodium nitroprusside to reduce blood pressure and arterial afterload. At baseline, patients had severe hypertension (aortic systolic pressure, 176±26 mm Hg), pulmonary hypertension (mean pressure, 39±12 mm Hg), elevated LV end-diastolic pressure (19±5 mm Hg), and reduced stroke volume (33±8 mL/m 2 ). All measures of afterload were reduced with nitroprusside ( P <0.001 for all). Nitroprusside reduced mean pulmonary artery pressure (25±10 mm Hg) and LV end-diastolic pressure (11±5 mm Hg; P <0.001 for both compared with baseline). Aortic valve area (0.86±0.11 to 1.02±0.16 cm 2 ; P =0.001) and mean gradient (27±5 to 29±6 mm Hg; P =0.02) increased with nitroprusside. Conclusions— Systemic hypertension in low-gradient severe aortic stenosis with preserved ejection fraction is associated with elevated LV filling pressures and pulmonary hypertension. Treatment of hypertension with vasodilator therapy results in a lowering of the total LV afterload, with a decrease in LV filling pressures and pulmonary artery pressures. These findings have important implications for the management of patients with low-gradient severe aortic stenosis with preserved ejection fraction and hypertension.

Retroperitoneal fibrosis is a rare condition characterized by the presence of inflammatory and fibrous retroperitoneal tissue that surrounds and often encases abdominal structures. In this report we describe an unusual presentation of retroperitoneal fibrosis and inferior vena cava (IVC) obstruction that was unidentified by noninvasive testing and ultimately diagnosed using exercise right heart catheterization and venography. Exercise hemodynamic catheterization revealed a high pressure gradient across the IVC obstruction during exercise that resulted in reduced preload and inappropriately low cardiac output reserve. The patient ultimately underwent angioplasty and stenting of the obstruction resulting in resolution of his symptoms. © 2013 Wiley Periodicals, Inc.

Background— The pathophysiology of low flow, low gradient severe aortic stenosis (LGSAS) with preserved ejection fraction is poorly understood. It has been proposed that abnormalities of arterial circulation are a major contributor to this syndrome. Methods and Results— We invasively examined systemic arterial afterload (effective arterial elastance, Ea; total arterial compliance, Ca; and systemic vascular resistance index) in patients with LGSAS (mean gradient, <40 mm Hg; aortic valve area, <1.0 cm 2 ) and preserved ejection fraction (≥50%), and compared these findings with patients with high gradient (≥40 mm Hg) severe aortic stenosis (HGSAS) and moderate AS (mean gradient, <40 mm Hg; aortic valve area, >1.0 cm 2 ). Patients with LGSAS (n=36), HGSAS (n=31), and moderate AS (n=19) were similar with respect to age, sex, body size, symptoms, comorbidities, and ejection fraction. Aortic valve area was similar between groups with LGSAS and HGSAS, but the patients with LGSAS had reduced stroke volume index and cardiac index ( P =0.003 for both). In comparison with patients with HGSAS and moderate AS, measures of afterload, including Ea (4.02±0.98 versus 3.13±0.81 and 3.06±0.79 mm Hg·m 2 /mL; P <0.0001) and systemic vascular resistance index (3116±799 versus 2515±645 and 2380±546 dyn·s·m 2 /cm 5 ; P =0.001), were significantly higher in LGSAS, whereas Ca was lower (0.46±0.16 versus 0.57±0.13 and 0.59±0.19 mL/m 2 per mm Hg; P =0.002). All invasive measures of arterial afterload were related to stroke volume index. Conclusions— Patients with LGSAS and preserved ejection fraction display elevated arterial afterload compared with patients with HGSAS and moderate AS. These findings identify systemic arterial effects that contribute to the hemodynamic presentation in patients with LGSAS and help to further define this entity.