Pulmonary embolism and pulmonary hypertension with suspected concomitant pulmonary arteriovenous malformation: A case report of clinical utility of right ventricular strain
Tóm tắt
Background
Venous thromboembolism (VTE) refers to a condition of thrombus formation in the peripheral extremities (deep vein thrombosis) and/or pulmonary vessels (pulmonary embolism) which may develop either spontaneously or provoked by triggering events such as trauma, surgery, and prolonged bed rest.1 VTE is the third giant killer next to stroke and myocardial infarction3, thus, its rapid diagnosis cannot be overly emphasized.
Methods
In this report, we present the case of a 58-year old Filipina who has been experiencing dyspnea and easy fatigability for one year. On physical examination, she was slightly tachypneic, with normal oxygenation at room air via pulse oximetry. She had an irregularly irregular cardiac rhythm and heave. The cardiac apex was not displaced and there was no appreciable murmur. A transthoracic echocardiogram with agitated saline contrast study showed dilated right cardiac chambers and left atrium, and late appearance of microbubbles on the left atrium signaling pulmonary arteriovenous malformation (PAVM). The conventional RV parameters – TAPSE and RVFAC – were both normal. However, the RV global longitudinal and free wall strains were -15.5% and -19.1%, respectively, implying a subclinical RV dysfunction. A CT Pulmonary angiogram showed dilated pulmonary trunk and right and left pulmonary arteries, with filling defects in multiple sites in the right pulmonary artery, which were consistent with pulmonary embolism with concomitant pulmonary hypertension. No PAVM was seen in the CTPA, hence we can surmise that it could be small and is not the primary culprit for the symptoms of our patient. The patient was then started with anticoagulant and phosphodiesterase-5 inhibitor.
Results
Chronic thromboembolic pulmonary hypertension (CTEPH), one of the known sequelae of pulmonary embolism (PE), can lead to right-sided heart failure and death.4 Right heart cathetherization (RHC) remains to be the confirmatory test for CTEPH.6 However, due to the invasive nature of RHC, studies believe that CTEPH remains to be underdiagnosed. Current guidelines recommend the use of echocardiography as the initial step among patients suspected of PE and CTEPH. PE alone may result to RV dilatation and/or hypokinesis or dyskinesia. However, the review of Tadic et al in 2021 concluded that standard RV parameters—RVFAC and TAPSE– have limited prognostic power due to load dependency and complexity of RV geometry. The use of strain can overcome such limitations, and subsequently detect subclinical RV damage even when the standard RV parameters appear to be normal. In our patient, her RVFAC and TAPSE were within normal limits, but her RV GLS imply subclinical dysfunction.
Conclusion
As a surrogate for right heart catheterization, hemodynamics and physiological assessment of the heart in these patients may be done with the use of echocardiography and other non-invasive tests. Furthermore, the use of newer parameters such as strain via speckle tracking, gives additional insight as to the systolic and diastolic functions of chamber/s being investigated. Such advancements will prevent delay of initiation of treatment in various cardiovascular diseases.
