Jessica A. Schumann | EM/IM PGY-3
The Article:
The Idea:
To explore the clinical utility of early systolic notching (ESN) of the right ventricular outflow tract (RVOT) pulsed-wave Doppler envelope in the detection of massive pulmonary embolism (MPE) or submassive pulmonary embolism (SMPE)
The Study:
Retrospective study at Wayne State University where 277 (187 with PE, 90 control subjects without PE) patients without known pulmonary hypertension, who underwent contrast computed tomographic angiography (CTA) for suspected pulmonary embolism (PE) and underwent transthoracic echocardiography within 48 hours were studied. Patients with suboptimal pulsed-wave Doppler signals across the RVOT, more than moderate valvular disease, known history of PE, established chronic thromboembolic pulmonary hypertension, and preexisting pulmonary hypertension were excluded from the study.
The authors also evaluated other echocardiographic parameters, including McConnell’s sign and 60/60 sign.
Doppler interrogation of the RVOT was performed in the parasternal short-axis view at the level of the aortic valve or from the subcostal short-axis view with sample volume placed approximately 0.5 cm proximal to pulmonic valve.
Early Systolic Notching: Early systolic notching pattern (spike and dome morphology) Doppler envelope exhibits a narrow peaked initial wave (spike) with early deceleration of the RVOT envelope producing a sharp notch within the first half of systole (notch location within initial 50% of ejection, estimated with caliper tool) followed by a second Doppler wave (dome) that was more curvilinear in appearance.
Midsystolic Notching: Midsystolic notching is defined as a distinct notch falling within the second half of the systolic ejection period or, if the nadir occurred closer to the end of ejection, dividing the flow profile into two distinct peaks
The Findings:
Two authors blinded to the PE diagnosis evaluated 277 patients’ echocardiograms. Of these patients, 187 patients had a PE diagnosed on CTA within 48 hours of the echocardiogram. There was good interobserver agreement (96.7%).
In patients with massive pulmonary embolus or submassive pulmonary embolus, early systolic notching was observed in 92% of patients and midsystolic notching was observed in 1% of these patients.
In patients with subsegmental pulmonary embolus, early systolic notching was observed in 2% of patients and midsystolic notching was observed in 16% of patients.
In the control group of 90 patients, no systolic notching was observed.
Early systolic notching pattern for MPE and SMPE was shown to have good to excellent predictive ability: 92% sensitive and 99% specific. ESN had a positive predictive value of 96% and a negative predictive value of 96%. This is superior predictive ability when compared to McConnell’s sign, which yielded a sensitivity of 52% in this study.
The Takeaway:
ESN reliably identified patients with MPE and SMPE, but it did not identify those with subsegmental PE. ESN demonstrated superior predictive value with a high negative predictive value. Echocardiography should not be viewed as the primary screening test or gatekeeper for CTA in the diagnosis of acute PE. Prospective studies are required in broader populations, and the findings will need validated. In the future, echocardiography may offer a more cost-effective screening tool when compared to CTA