Clinical outcomes of percutaneous debulking of tricuspid valve endocarditis in intravenous drug users.

OBJECTIVES: A retrospective case series of a percutaneous approach to debulk tricuspid valve endocarditis (TVE) using an 8 French mechanical aspiration system in patients with a history of intravenous drug use (IVDU) was reported. IVDU associated TVE is increasing in the United States and is associated with high mortality despite early surgical debridement. Patients with advanced disease, shock, and respiratory failure may not be candidates for surgical debridement or replacement. These patients have recurrent events despite medical therapy METHODS: About 25 patients with IVDU associated TVE with persistent bacteremia confirmed by repeat blood cultures after 72 hr of sensitivity directed antibiotics and presence of pulmonary emboli confirmed by computed tomographic (CT) scan, who had undergone percutaneous aspiration were included. Patients were all deemed high risk for surgical debridement by a CT surgeon and evaluated by an infectious disease consultant. Procedures were performed under moderate sedation with intracardiac echo and a steerable guide with a CAT8 Penumbra aspiration catheter. RESULTS: There were no intraprocedural deaths or complications. About 36% had septic shock on presentation. Survival of index hospitalization was 88%. Repeat blood cultures showed no growth on all surviving patients. Readmission rate was 4% (n = 1) at 1 month. About 40% (n = 2) patients with septic shock survived at 1 month compared with 100% survival (n = 20) in those without shock. Presence of septic shock was associated with reduced survival at 1 month (p < .01). CONCLUSION: Percutaneous mechanical aspiration with an 8 Fr system is a feasible, minimally invasive alternative to surgical debulking. Mortality remains high in those presenting with septic shock. Further studies are needed to evaluate long-term outcomes.

Longitudinal impedance is independent of outflow resistance.

BACKGROUND: Many investigators have measured outflow resistance (R) following peripheral bypass procedures, but correlations with graft patency have been weak. This is because the primary determinants of graft patency are the size and quality of the conduit, not its outflow bed. Efforts at separating conduit resistance from outflow resistance have been unsuccessful. Recently, the concept of longitudinal impedance ( integral Z(L)) has been suggested as a measure of conduit resistance independent of outflow resistance. The purpose of this in vitro experiment was to test the hypothesis that integral Z(L) is independent of R within physiologically relevant ranges. METHODS: Rigid polyethylene tubing of known internal diameter and length (4.3 mm, 375 cm) was perfused with a glycerin/saline mixture mimicking the viscosity of blood (4.1 cp), utilizing a variable pulsatile pump and Windkessel, with outflow into multiply branched tubes of decreasing diameter simulating the hemodynamic conditions of arterial bypass. Flow and pressure were measured using ultrasonic transit time and catheter transduction, respectively, and waveforms digitized at 200 Hz. Flow was varied while maintaining "systemic" pressure and resistance. After Fourier transformation, integral Z(L) was calculated as deltaP/Q at each harmonic and integrated over 4 Hz. RESULTS: integral Z(L) calculations were remarkably reproducible within the same day with a coefficient of variation (CV) = 4.0% (at 100 dyne. s/cm(5); n = 4) or over 4 successive days (CV = 4.3%). Furthermore, integral Z(L) was largely independent of R over the physiologic range tested, with integral Z(L) remaining relatively constant as R was increased sixfold. CONCLUSION: integral Z(L) is a consistent and reproducible measure of conduit resistance independent of R over a wide physiologic range. It may be useful for measuring the adequacy of bypass graft conduits.