Clot distribution in pulmonary embolism does not influence right ventricular recovery
Hines J, Floyd M, Ismail R, Le P, Grafton G, Kelly B, Hegab S, and Awdish RL. Clot distribution in pulmonary embolism does not influence right ventricular recovery. American Journal of Respiratory and Critical Care Medicine 2020; 201(1).
American Journal of Respiratory and Critical Care Medicine
Rationale: The incidence of acute pulmonary embolism (APE) is estimated at 1-2 per 1,000 persons with VTE responsible for 60,000-100,000 deaths annually. This is likely an underestimate given 10-30% will die within one month of diagnosis. Catheter directed thrombolysis (CDT) has been shown to improve right ventricular (RV) function, however it is unknown if clot distribution is a predictor of RV recovery. Additionally, it is unknown if thrombolytic bolus dosing impacts RV recovery after CDT.
Methods: We conducted a retrospective review of patients in our Pulmonary Embolism Response Team (PERT) database from May 2017 to present who had undergone CDT due to RV strain on either chest computed tomography (CT) or echocardiogram RV strain on CT was defined as RV/LV ratio > 0.9, flattening of the interventricular septum, and reflux of contrast into the venous circulation (Dudzinski et. al 2016). RV strain on echo was defined as RV dilation > 1:1 and tricuspid annular plane systolic excursion (TAPSE) < 1.8 (Roberts et. al 2011). Clot burden was defined by the Miller score (Ouriel et. al 2017) and most central location of the embolism. The primary endpoint of RV recovery was defined as no RV dilation and TAPSE > 1.8 post CDT.
Results: 101 patients underwent CDT with a mean age of 57; 51% were male. The proportion of patients with main pulmonary artery and saddle APE were 91% and 36% respectively. Univariate associations with RV recovery were carried out using chisquared or Fisher's exact tests for categorical variables and analysis of variance for continuous variables (statistical significance p < 0.05). At 24-72 hours and 3 months, 12/48 (25%) and 34/48 (71%) patients respectively had RV recovery. Clot distribution was not significantly associated with RV recovery, nor was the Miller score. Higher dose lytic bolus was associated with increased RV recovery (p=0.016) and more significant non-fatal bleeding events. Elevated heart rate (HR) initially was associated with inability to recover RV function (HR 99.7 ± 14.3 without RV recovery; and 92.2 ± 13.6 with RV recovery) (p=0.028).
Conclusions: Distribution of APE does not appear to influence RV recovery after CDT. As expected, 100% of patients with echocardiographic data at 3 months recovered RV function. Bolus dose of lytic and HR prior to CDT appear to be associated with RV recovery. To our knowledge, this is the first study to indicate that higher dose lytic bolus during CDT is associated with RV recovery.