Adjusting Atrial Size Parameters for Body Surface Area: Does it Affect the Association With Pulmonary Embolism-related Adverse Events?

PURPOSE: Small left atrial (LA) volume was recently reported to be one of the best predictors of acute pulmonary embolism (PE)-related adverse events (AE). There is currently no data available regarding the impact that body surface area (BSA)-indexing of atrial measurements has on the association with PE-related adverse events. Our aim is to assess the impact of indexing atrial measurements to BSA on the association between computed tomography (CT) atrial measurements and AE. MATERIALS AND METHODS: Retrospective study (IRB: 2015P000425). A database of hospitalized patients with acute PE diagnosed on CT pulmonary angiography (CTPA) between May 2007 and December 2014 was reviewed. Right and left atrial volume, largest axial area, and axial diameters were measured. Patients undergo both echocardiographies (from which the BSA was extracted) and CTPAs within 48 hours of the procedure. The patient's body weight was measured during each admission. LA measurements were correlated to AE (defined as the need for advanced therapy or PE-related mortality at 30 days) before and after indexing for BSA. The area under the ROC curve was calculated to determine the predictive value of the atrial measurements in predicting AE. RESULTS: The study included 490 acute PE patients; 62 (12.7%) had AE. There was a significant association of reduced BSA-indexed and non-indexed LA volume (both <0.001), area (<0.001 and 0.001, respectively), and short-axis diameters (both <0.001), and their respective RA/LA ratios (all <0.001) with AE. The AUC values were similar for BSA-indexed and non-indexed LA volume, diameters, and area with LA volume measurements being the best predictor of adverse outcomes (BSA-indexed AUC=0.68 and non-indexed AUC=0.66), followed by non-indexed LA short-axis diameter (indexed AUC=0.65, non-indexed AUC=0.64), and LA area (indexed AUC=0.64, non-indexed AUC=0.63). CONCLUSION: Adjusting for BSA does not substantially affect the predictive ability of atrial measurements on 30-day PE-related adverse events, and therefore, this adjustment is not necessary in clinical practice. While LA volume is the better predictor of AE, LA short-axis diameter has a similar predictive value and is more practical to perform clinically.

Evidence for Left Atrial Volume Being an Indicator of Adverse Events in Patients With Acute Pulmonary Embolism: Retrospective Case-control Pilot Study.

PURPOSE: To assess the association between computed tomography pulmonary angiography (CTPA) atrial measurements and both 30-day pulmonary embolism (PE)-related adverse events and mortality, and non-PE-related mortality, and to identify the best predictors of these outcomes by comparing atrial measurements and widely used clinical and imaging variables. PATIENTS AND METHODS: Retrospective single-center pilot study. Acute PE patients diagnosed on CTPA who also had a transthoracic echocardiogram, electrocardiogram, and troponin T were included. CTPA left atrial (LA) and right atrial (RA) volume and short-axis diameter were measured and compared between outcome groups, along with right ventricular/left ventricular diameter ratio, interventricular septal bowing, tricuspid annular plane systolic excursion, electrocardiogram, and troponin T. RESULTS: A total of 350 patients. LA volume and diameter were associated with PE-related adverse events (P≤0.01). LA volume was the only atrial measurement associated with PE-related mortality (P=0.03), with no atrial measurements associated with non-PE-related mortality. Troponin was most associated with PE-related adverse events and mortality (both area under the curve [AUC]=0.77). On multivariate analysis, combination models did not greatly improve PE-related adverse events prediction compared with troponin alone. For PE-related mortality, the best models were the combination of troponin, age, and either LA volume (AUC=0.86) or diameter (AUC=0.87). CONCLUSION: Among patients with acute PE, CTPA LA volume is the only imaging parameter associated with PE-related mortality and is the best imaging predictor of this outcome. Reduced CTPA LA volume and diameter, along with increased RA/LA volume and diameter ratios, are significantly associated with 30-day PE-related adverse events, but not with non-PE-related mortality.

Multimodality Assessment of Right Ventricular Strain in Patients With Acute Pulmonary Embolism.

Optimal risk stratification is essential in managing patients with an acute pulmonary embolism (PE). There are limited data evaluating the potential additive value of various methods of evaluation of right ventricular (RV) strain in PE. We retrospectively evaluated RV strain by computed tomography (CT), transthoracic echocardiography (TTE), electrocardiography (ECG), and troponin levels in consecutive hospitalized patients with acute PE (May 2007 to December 2014). Four-hundred and seventy-seven patients met inclusion criteria. RV strain on ECG (odds ratio [OR] 1.9, confidence interval [CI] 1.1 to 3.3; p = 0.03), CT (OR 2.7, CI 1.5 to 4.8, p <0.001), TTE (OR 2.8, CI 1.5 to 5.4, p <0.001), or a positive troponin (OR 2.7, CI 2.0 to 6.9, p <0.001) were associated with adverse events. In patients with ECG, CT, and TTE data, increased risk was only elevated with RV strain on all 3 parameters (OR 4.6, CI 1.8 to 11.3, p <0.001). In all patients with troponin measurements, risk was only elevated with RV strain on all 3 parameters plus a positive troponin (OR 8.8, CI 2.8 to 28.1, p <0.001) and was similar in intermediate-risk PE (OR 11.1, CI 1.2 to 103.8, p = 0.04). In conclusion, in patients with an acute PE and evaluation of RV strain by ECG, CT, and TTE, risk of adverse events is only elevated when RV strain is present on all 3 modalities. Troponin further aids in discriminating high-risk patients. Multimodality assessment of RV strain is identified as a superior approach to risk assessment.