Link to Abstract-
During structural heart procedures, invasive pressure-volume loop analysis enables for direct monitoring of changing intraventricular cardiac mechanics. The goal of this study was to show how right and left ventricular mechanics changed after transcatheter edge-to-edge tricuspid regurgitation correction. (Advanced level of difficulty.)
Despite receiving optimal medical therapy, an 84-year-old woman with known right ventricular (RV) heart failure due to severe tricuspid valve insufficiency presented to a peripheral hospital with decreased exercise tolerance and progressive reports of dyspnea (New York Heart Association functional class IV). She was normotensive with bimalleolar edema on physical examination. In the presence of atrial dilatation and severe tricuspid regurgitation with a massive central jet and no further significant valvular disease, transthoracic and transesophageal echocardiography revealed normal left ventricular (LV) and reduced RV function (adequate longitudinal contraction but severely reduced radial contraction) (Figure 1). For endovascular tricuspid valve repair, the patient was referred to our center (Thorax Center, Erasmus University Medical Center, Rotterdam, the Netherlands).
Previous Medical Experience
Hypertension, chronic obstructive pulmonary disease, transient ischemic attack, and atrial fibrillation were among the patient's medical conditions.
Differential Diagnosis is a term used to describe the process of distinguishing between two
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Because of her age and frailty (The Society of Thoracic Surgeons score, 3.7 percent), the patient was turned down for surgical tricuspid valve replacement and was instead scheduled for transcatheter edge-to-edge tricuspid valve repair (TEETR) with comprehensive periprocedural hemodynamic monitoring.
TEETR was conducted under general anesthesia with the patient under transesophageal echocardiographic supervision. A pulmonary artery catheter and a conductance catheter were used for periprocedural hemodynamic monitoring, providing pressure-volume loop (PVL) monitoring (CD Leycom). Before and after TEETR, a comprehensive invasive hemodynamic assessment was performed, including PVL measurement of the right and left ventricles. The conductance catheter remained at the apex of the left ventricle during TEETR. The volume calibration of the conductance catheter was done with thermodilution, and parallel conductance was determined with hypertonic saline. Following a conduction catheter exchange between the right and left ventricles, volume calibration and parallel conductance measurements were repeated. Under fluoroscopic guidance and visual inspection of segmental loops, the conduction catheter was positioned in the ventricular apex, ensuring that the segments were in the same place within the appropriate chamber during data gathering. End-systolic elastance (Ees) was calculated using single-beat maximal pressure (Pmax). The patient exhibited atrial fibrillation with little beat-to-beat abnormalities during the operation. Along the septal-anterior commissure, two clips (TriClip XT, Abbott) were used (Figure 1). Figure 2 summarizes LV and RV PVL plots with matching end-systolic pressure-volume and end-diastolic pressure-volume relationships, both before and after TEETR, with corresponding quantifications in Table 1.
Cardiac output increased from 2.9 liters per minute before TEETR to 3.4 liters per minute after TEETR. After TEETR, LV PVL migrated rightward, with LV end-diastolic volume increasing from 77.9 to 105.6 mL and LV stroke volume increasing from 53.4 to 67.9 mL. TEETR reduced RV end-diastolic volume from 101.9 to 84.3 mL. After TEETR, the right ventricle's tau, a constant indicating the exponential reduction in ventricular pressure during the early relaxation period of diastole, reduced from 187.7 to 70.7 ms. After TEETR, the RV's stroke work (SW) and pressure-volume area (PVA) decreased (with a higher SW/PVA ratio of 0.54 to 0.68), indicating enhanced mechanical efficiency. Furthermore, TEETR improved RV systolic and diastolic intraventricular dyssynchrony (32.6 percent to 10.0 percent and 28.8 percent to 12.4 percent , respectively). The RV ratio of end-systolic elastance (Ees) to effective arterial elastance (Ea) (Ees/Ea) (representing right ventricular-pulmonary artery coupling) increased from 0.43 to 0.98, resulting in a drop in RV regurgitant volume from 44 to 7 mL. After TEETR, the RV ejection percent reduced (60.4 percent to 47.0 percent ). Maximal RV dP/dt (rate of rise in ventricular pressure) was reduced by half after TEETR, whereas Emax (maximal elastance) remained unchanged (0.44 to 0.41 mm Hg/mL).
The purpose of TEETR is to prevent tricuspid regurgitation in the right ventricle. Invasive PVL analysis can be used to document in situ the biventricular hemodynamic effects of structural heart operations, giving researchers a better understanding of cardiac mechanics. The SW/PVA ratio increased following TEETR, indicating a decrease in RV myocardial energy demand. Although the RV ejection fraction fell slightly (47%), intraventricular systolic and diastolic dyssynchrony improved. Furthermore, as a result of the enhanced pulmonary flow caused by TEETR, RV Ees/Ea rose. The load-independent Ees more than doubled, indicating a better cardiac contractile condition (1). Ea was a stable indicator of pulmonary vascular resistance and consequently RV afterload. The RV maximum dP/dt decreased following TEETR, however this is a heavily load-dependent measure. The RV volume at 15 mm Hg (V15mmHg) and mechanical intraventricular dyssynchrony, on the other hand, reduced, indicating better myocardial intrinsic contractility. These properties, together with a higher SW/PVA ratio, point to a significant increase in RV efficiency.
TEETR elevated LV preload and LV myocardial metabolic demand, as measured by LV end-diastolic volume, SW, and PVA. These events, on the other hand, were well tolerated and were linked to enhanced overall cardiac output, LV stroke volume, and steady LV intraventricular dyssynchrony and Ees/Ea (ie, LV-aortic coupling). In 18 patients up to 6 months following TEETR, PVL observations of increased LV filling (reflected by higher LV end-diastolic volume and stroke volume) and reduced RV loading were in agreement with cardiac magnetic resonance–based visualizations by Rommel et al (2). There are various limits to PVL analysis in this scenario. Thermodilution-based cardiac output measurement in the context of valvular insufficiency has inherent limitations that were not confirmed by a second (e.g., Fick) test. Furthermore, parallel conductance was evaluated using hypertonic saline; however, clip material influence with RV or LV conductance cannot be ruled out.
TEETR resulted in a considerable reduction in tricuspid regurgitation from enormous to mild or moderate, according to a transthoracic echocardiogram performed before discharge (Figure 1).
In a patient with significant isolated tricuspid regurgitation, invasive PVL study revealed immediate beneficial cardiomechanical effects of TEETR. TEETR produced the following results: 1) improved intraventricular dyssynchrony; 2) enhanced LV loading and LV myocardial metabolic demand; and 3) increased RV unloading, increased pulmonary artery flow, and lowered RV myocardial metabolic demand.
Author Disclosures and Funding Support
PulseCath BV has paid personal fees to Dr. Barros Bastos. CD Leycom and Dr. Schreuder have a working and financial relationship, according to Dr. Schreuder. Dr. Daemen has received institutional grants and research support from AstraZeneca, Abbott Vascular, Boston Scientific, ACIST Medical, Medtronic, Pie Medical, Siemens Health Care, and ReCor Medical, as well as consulting and speaker fees from Abiomed, ACIST Medical, Boston Scientific, ReCor Medical, PulseCath, Pie Medical, Siemens Health Care, and ReCor Medical. Abbott Vascular, Boston Scientific, Edwards Lifesciences, Medtronic, PulseCath BV, Abiomed, Daiichi Sankyo, and Siemens have all given Dr. Van Mieghem research grants. Dr. van den Enden has disclosed that he has no ties to disclose that are relevant to the content of this paper.