Pulmonary Vein Systolic Flow Reversal and Outcomes in Patients From the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation (COAPT) Trial.

Background: The implications of pulmonary vein (PV) flow patterns in patients with heart failure (HF) and mitral regurgitation (MR) are uncertain. We examined PV flow patterns in the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation (COAPT) trial (NCT01626079), in which patients with HF and moderate-to-severe or severe functional MR were randomized to transcatheter edge-to-edge repair (TEER) with the MitraClip device plus guideline-directed medical therapy (GDMT) vs. GDMT alone. We sought to evaluate the prognostic utility of baseline PV systolic flow reversal (PVSFR) in HF patients with severe MR and to determine whether the presence of PVSFR can discriminate patients most likely to benefit from TEER in COAPT trial patients. Methods: Patients were categorized by the echocardiographic core laboratory-assessed baseline presence of PVSFR. Two-year outcomes were examined according to PVSFR and treatment. Results: Baseline PV flow patterns were evaluable in 526/614(85.7%) patients, 48.9% of whom had PVSFR. Patients with PVSFR had more severe MR, reduced stroke volume and cardiac output, greater right ventricular dysfunction, and worse hemodynamics. By multivariable analysis, PVSFR was not an independent predictor of 2-year all-cause death, or heart failure hospitalization (HFH). The reductions in the 2-year rates of all-cause death and HFH with TEER compared with GDMT alone were similar in patients with and without PVSFR (Pinteraction = 0.40 and 0.12, respectively). The effect of TEER on improving Kansas City Cardiomyopathy Questionnaire scores and 6-minute walk distance were also independent of PVSFR. Conclusions: In the COAPT trial, PVSFR identified HF patients with severe MR and more advanced heart disease. Patients with and without PVSFR had consistent reductions in mortality, HFH, and improved quality-of-life and functional capacity after TEER. Clinical Trial Registration: ClinicalTrial.gov IdentifierNCT01626079.

Cross-Validation of Risk Scores for Patients Undergoing Transcatheter Edge-to-Edge Repair for Mitral Regurgitation.

Background: Risk scores may identify patients with mitral regurgitation (MR) who are at risk for adverse events, but who may still benefit from transcatheter edge-to-edge repair (TEER). We sought to cross-validate the MitraScore and COAPT risk score to predict adverse events in patients undergoing TEER. Methods: MitraScore validation was carried out in the COAPT population which included 614 patients with FMR who were randomized 1:1 to guideline-directed medical therapy (GDMT) with or without TEER and were followed for 2 years. Validation of the COAPT risk score was carried out in 1007 patients from the MIVNUT registry of TEER-treated patients with both FMR and degenerative MR who were followed for a mean of 2.1 years. The predictive value was assessed using the area under the receiver operating characteristic curve (AUC) plots. The primary outcome was all-cause mortality. Results: The MitraScore had fair to good predictive accuracy for mortality in the overall COAPT trial population (AUC, 0.67); its accuracy was higher in patients treated with TEER (AUC, 0.74) than GDMT alone (AUC, 0.65). The COAPT risk score had fair predictive accuracy for death in the overall MitraScore cohort (AUC, 0.64), which was similar in patients with FMR and degenerative MR (AUC, 0.64 and 0.66, respectively). There was a consistent benefit of treatment with TEER plus GDMT compared with GDMT alone in the COAPT trial population across all MitraScore risk strata. Conclusions: The COAPT risk score and MitraScore are simple tools that are useful for the prediction of 2-year mortality in patients eligible for or undergoing treatment with TEER.

Changes in Left Ventricular Function and Outcomes After Trancatheter Edge-to-Edge Repair for Secondary Mitral Regurgitation.

Background: Transcatheter edge-to-edge repair (TEER) improved outcomes in patients with heart failure (HF) and severe secondary mitral regurgitation (SMR) compared with guideline-directed medical therapy (GDMT) alone regardless of the severity of baseline left ventricular ejection fraction (LVEF). The study aimed to evaluate the effect of early changes in LVEF after TEER and GDMT alone in patients with HF and severe SMR. Methods: Within the COAPT trial, we evaluated outcomes according to changes in LVEF from baseline to 30 days. The primary outcome was all-cause death or HF hospitalization (HFH) between 30 days and 2 years. Results: Among 432 patients with paired echocardiographic data, 182 (42.1%) had increased LVEF (LVEF change 6.0% ± 4.9%) and 250 (57.9%) had a decrease or no change in LVEF (LVEF change -6.6% ± 5.6%) from baseline to 30 days. LVEF at 30 days increased more frequently with GDMT alone compared with TEER plus GDMT (51.4% vs 33.0%; P = .0001). Between 30 days and 2 years, there were no significant differences in death or HFH in the increase LVEF and the decrease LVEF groups (58.8% vs 51.4%; multivariable-adjusted HR, 0.97; 95% CI, 0.87-1.08; P = .59). TEER plus GDMT reduced the 30-day to 2-year rate of death or HFH compared with GDMT alone consistently in patients with increase LVEF and decrease LVEF (Pint = 0.75). Conclusions: Among patients with HF and severe SMR, early improvements in LVEF were more frequent with GDMT alone compared with TEER plus GDMT but were not associated with subsequent outcomes at 2 years. TEER reduced death or HFH during 2-year follow-up irrespective of early LVEF changes.

TRISCEND II: Novel Randomized Trial Design for Transcatheter Tricuspid Valve Replacement.

Severe tricuspid regurgitation remains largely undertreated given limited treatment options. Transcatheter tricuspid valve interventions have emerged as a promising therapy for these patients, and the TRISCEND II pivotal trial is the first randomized controlled trial to evaluate transcatheter tricuspid valve replacement (TTVR). The TRISCEND II pivotal trial studies the transcatheter EVOQUE (Edwards Lifesciences, Irvine, California) tricuspid valve replacement system using a United States Food and Drug Administration Breakthrough Device Designation-a program intended to provide timely access to medical devices by speeding up development, assessment, and review. The TRISCEND II trial is a prospective, multicenter trial that randomizes patients with symptomatic severe tricuspid regurgitation to treatment with either TTVR in conjunction with optimal medical therapy or optimal medical therapy alone. The trial's novel 2-phase design evaluates 30-day safety and 6-month effectiveness end points for the first 150 patients in the initial phase and a 1-year safety and effectiveness end point for the full cohort of 400 patients in the second phase. The TRISCEND II trial's 2-phase trial design provided an opportunity for early review and led to the first commercial approval of a TTVR system. In conclusion, the design of the TRISCEND II trial will likely inform future transcatheter tricuspid device trials.

Left Atrial Improvement in Patients With Secondary Mitral Regurgitation and Heart Failure: The COAPT Trial.

BACKGROUND: Functional mitral regurgitation induces adverse effects on the left ventricle and the left atrium. Left atrial (LA) dilatation and reduced LA strain are associated with poor outcomes in heart failure (HF). Transcatheter edge-to-edge repair (TEER) of the mitral valve reduces heart failure hospitalization (HFH) and all-cause death in selected HF patients. OBJECTIVES: The aim of this study was to evaluate the impact of LA strain improvement 6 months after TEER on the outcomes of patients enrolled in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial. METHODS: The difference in LA strain between baseline and the 6-month follow-up was calculated. Patients with at least a 15% improvement in LA strain were labeled as "LA strain improvers." All-cause death and HFH were assessed between the 6- and 24-month follow-up. RESULTS: Among 347 patients (mean age 71 ± 12 years, 63% male), 106 (30.5%) showed improvement of LA strain at the 6-month follow-up (64 [60.4%] from the TEER + guideline-directed medical therapy [GDMT] group and 42 [39.6%] from the GDMT alone group). An improvement in LA strain was significantly associated with a reduction in the composite of death or HFH between the 6-month and 24-month follow-up, with a similar risk reduction in both treatment arms (Pinteraction = 0.27). In multivariable analyses, LA strain improvement remained independently associated with a lower risk of the primary composite endpoint both as a continuous variable (adjusted HR: 0.94 [95% CI: 0.89-1.00]; P = 0.03) and as a dichotomous variable (adjusted HR: 0.49 [95% CI: 0.27-0.89]; P = 0.02). The best outcomes were observed in patients treated with TEER in whom LA strain improved. CONCLUSIONS: In symptomatic HF patients with severe mitral regurgitation, improved LA strain at the 6-month follow-up is associated with subsequently lower rates of the composite endpoint of all-cause mortality or HFH, both after TEER and GDMT alone. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [COAPT]; NCT01626079).

Comparison of Transcatheter Edge-to-Edge Mitral Valve Repair for Primary Mitral Regurgitation Outcomes to Hospital Volumes of Surgical Mitral Valve Repair.

BACKGROUND: Transcatheter edge-to-edge mitral valve (MV) repair (TEER) is an effective treatment for patients with primary mitral regurgitation at prohibitive risk for surgical MV repair (MVr). High-volume MVr centers and high-volume TEER centers have better outcomes than low-volume centers, respectively. However, whether MVr volume predicts TEER outcomes remains unknown. We hypothesized that high-volume MV surgical centers would have superior risk-adjusted outcomes for TEER than low-volume centers. METHODS: We combined data from the American College of Cardiology/Society of Thoracic Surgeons Transcatheter Valve Therapy registry and the Society of Thoracic Surgeons adult cardiac surgery database. MVr was defined as leaflet resection or artificial chords with or without annuloplasty and was evaluated as a continuous variable and as predefined categories (<25, 25-49, and ≥50 MV repairs/year). A generalized linear mixed model was used to evaluate risk-adjusted in-hospital/30-day mortality, 30-day heart failure readmission, and TEER success (mitral regurgitation ≤2+ and gradient <5 mm Hg). RESULTS: The study comprised 41 834 patients from 500 sites of which 332 (66.4%) were low, 102 (20.4%) intermediate, and 66 (13.2%) high-volume surgical centers (P<0.001). TEER success was 54.6% and was not statistically significantly different across MV surgical site volumes (P=0.4271). TEER mortality at 30 days was 3.5% with no significant difference across MVr volume on unadjusted (P=0.141) or adjusted (P=0.071) analysis of volume as a continuous variable. One-year mortality was 15.0% and was lower for higher MVr volume centers when adjusted for clinical and demographic variables (P=0.027). Heart failure readmission at 1 year was 9.4% and was statistically significantly lower in high-volume centers on both unadjusted (P=0.017) or adjusted (P=0.015) analysis. CONCLUSIONS: TEER can be safely performed in centers with low volumes of MV repair. However, 1-year mortality and heart failure readmission are superior at centers with higher MVr volume.

Right Heart Remodeling and Outcomes in Patients With Tricuspid Regurgitation: A Literature Review and Meta-Analysis.

BACKGROUND: Functional tricuspid regurgitation (TR) can develop either because of right ventricular (RV) remodeling (ventricular functional TR) and/or right atrial dilation (atrial functional TR). OBJECTIVES: This meta-analysis aimed to investigate the association between right heart remodeling and long-term (>1 year) all-cause mortality in patients with significant TR (at least moderate, ≥2+). METHODS: MEDLINE, ISI Web of Science, and SCOPUS databases were searched. Studies reporting data on at least 1 RV functional parameter and long-term all-cause mortality in patients with significant TR were included. This study was designed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) requirements. RESULTS: Out of 8,902 studies, a total of 14 were included, enrolling 4,394 subjects. The duration of follow-up across the studies varied, ranging from a minimum of 15.5 months to a maximum of 73.2 months. Overall, long-term all-cause mortality was 31% (95% CI: 20%-41%; P ≤ 0.001). By means of meta-regression analyses, an inverse relation was found between tricuspid annular plane systolic excursion (11 studies enrolling 3,551 subjects, -6.3% [95% CI: -11.1% to -1.4%]; P = 0.011), RV fractional area change (9 studies, 2,975 subjects, -4.4% [95% CI: -5.9% to -2.9%]; P < 0.001), tricuspid annular dimension (7 studies, 2,986 subjects, -4.1% [95% CI: -7.6% to -0.5%]; P = 0.026), right atrial area (6 studies, 1,920 subjects, -1.9% [95% CI: -2.5% to -1.3%]; P < 0.001) and mortality. CONCLUSIONS: RV dysfunction parameters are associated to worse clinical outcomes in patients with TR, whereas right atrial dilatation is linked to a better prognostic outcome. Further studies are needed to unravel the pathophysiological differences within the functional TR spectrum. (Right heart remodeling and outcomes in patients with tricuspid regurgitation; CRD42023418667).

The Evolving Concept of Secondary Mitral Regurgitation Phenotypes: Lessons From the M-TEER Trials.

Conflicting results from 2 randomized clinical trials of transcatheter mitral valve edge-to-edge repair in secondary mitral regurgitation (SMR) have led to the recognition that SMR is a heterogeneous disease entity presenting with different functional and morphological phenotypes. This review summarizes the current knowledge on SMR caused primarily by atrial secondary mitral regurgitation (aSMR) and ventricular SMR pathology. Although aSMR is generally characterized by severe left atrial enlargement in the setting of preserved left ventricular anatomy and function, different patterns of mitral annular distortion cause different phenotypes of aSMR. In ventricular SMR, the relation of SMR severity to left ventricular dilation as well as the degree of pulmonary hypertension and right ventricular dysfunction are important phenotypic characteristics, which are key for a better understanding of prognosis and treatment response.

Tricuspid regurgitation burden following transcatheter aortic valve replacement requiring early pacemaker implantation.

Background: Conduction abnormality requiring the implantation of a permanent pacemaker (PPM) is a well-known and clinically important complication of transcatheter aortic valve replacement (TAVR). However, PPM implantation may result in lead-associated tricuspid valve regurgitation (TR). This study sought to determine the incidence and progression of TR following PPM implantation after TAVR. Methods: This was a retrospective review of all echocardiograms of patients who underwent PPM following TAVR at the Baylor Scott & White hospitals from 2012 to 2021. The primary endpoint was TR progression at 30 days and 1 year. A subanalysis comparing the change in TR progression between small and large TAVR devices was also conducted. Secondary outcomes included all-cause death at 30 days and 1 year. Results: Out of the 2744 patients who underwent TAVR between April 2012 and August 2021, 177 patients (6.5%) subsequently received a new PPM. There was a statistically significant progression of TR at 1-year follow-up (McNemar's P value = 0.02). TR progression rates were comparable between the small and large valve groups at 1-year follow-up (4% vs 11%, P = 0.09, respectively). Conclusion: In this single healthcare system study, we demonstrated a significant progression of TR in patients with PPM post TAVR at 1 year.

Echocardiographic Outcomes With Transcatheter Edge-to-Edge Repair for Degenerative Mitral Regurgitation in Prohibitive Surgical Risk Patients.

BACKGROUND: The CLASP IID randomized trial (Edwards PASCAL TrAnScatheter Valve RePair System Pivotal Clinical Trial) demonstrated the safety and effectiveness of the PASCAL system for mitral transcatheter edge-to-edge repair (M-TEER) in patients at prohibitive surgical risk with significant symptomatic degenerative mitral regurgitation (DMR). OBJECTIVES: This study describes the echocardiographic methods and outcomes from the CLASP IID trial and analyzes baseline variables associated with residual mitral regurgitation (MR) ≤1+. METHODS: An independent echocardiographic core laboratory assessed echocardiographic parameters based on American Society of Echocardiography guidelines focusing on MR mechanism, severity, and feasibility of M-TEER. Factors associated with residual MR ≤1+ were identified using logistic regression. RESULTS: In 180 randomized patients, baseline echocardiographic parameters were well matched between the PASCAL (n = 117) and MitraClip (n = 63) groups, with flail leaflets present in 79.2% of patients. Baseline MR was 4+ in 76.4% and 3+ in 23.6% of patients. All patients achieved MR ≤2+ at discharge. The proportion of patients with MR ≤1+ was similar in both groups at discharge but diverged at 6 months, favoring PASCAL (83.7% vs 71.2%). Overall, patients with a smaller flail gap were significantly more likely to achieve MR ≤1+ at discharge (adjusted OR: 0.70; 95% CI: 0.50-0.99). Patients treated with PASCAL and those with a smaller flail gap were significantly more likely to sustain MR ≤1+ to 6 months (adjusted OR: 2.72 and 0.76; 95% CI: 1.08-6.89 and 0.60-0.98, respectively). CONCLUSIONS: The study used DMR-specific echocardiographic methodology for M-TEER reflecting current guidelines and advances in 3-dimensional echocardiography. Treatment with PASCAL and a smaller flail gap were significant factors in sustaining MR ≤1+ to 6 months. Results demonstrate that MR ≤1+ is an achievable benchmark for successful M-TEER. (Edwards PASCAL TrAnScatheter Valve RePair System Pivotal Clinical Trial [CLASP IID]; NCT03706833).

Regurgitant Volume to LA Volume Ratio in Patients with Secondary MR: The COAPT Trial.

AIMS: The conceptual framework of proportionate versus disproportionate mitral regurgitation (MR) translates poorly to individual patients with heart failure (HF) and secondary MR. A novel index, the ratio of MR severity to left atrial volume (LAV), may identify patients with "disproportionate" MR and a higher risk of events. The objectives, therefore, were to investigate the prognostic impact of MR severity to LAV ratio on outcomes among HF patients with severe secondary MR randomized to transcatheter edge-to-edge repair (TEER) with the MitraClipTM device plus guideline-directed medical therapy (GDMT) vs. GDMT alone in the COAPT trial. METHODS AND RESULTS: The ratio of preprocedural regurgitant volume (RVol) to LAV was calculated from baseline transthoracic echocardiograms. The primary endpoint was 2-year covariate-adjusted rate of HF hospitalization (HFH).Among 567 patients, the median RVol/LAV was 0.67 (IQR 0.48-0.91). In patients randomized to GDMT alone, lower RVol/LAV was independently associated with an increased 2-year risk of HFH (adjHR: 1.77; 95% CI: 1.20-2.63). RVol/LAV was a stronger predictor of adverse outcomes than RVol or LAV alone. Treatment with TEER plus GDMT compared with GDMT alone was associated with lower 2-year rates of HFH both in patients with low and high RVol/LAV (Pinteraction = 0.28). Baseline RVol/LAV ratio was unrelated to 2-year mortality, health status, or functional capacity in either treatment group. CONCLUSIONS: Low RVol/LAV ratio was an independent predictor of 2-year HFH in HF patients with severe MR treated with GDMT alone in the COAPT trial. TEER improved outcomes regardless of baseline RVol/LAV ratio. CLINICAL TRIAL REGISTRATION: Trial Name: Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation (The COAPT Trial) (COAPT) ClinicalTrial.gov Identifier: NCT01626079 URL: https://clinicaltrials.gov/ct2/show/NCT01626079.

Transfemoral tricuspid valve replacement and one-year outcomes: the TRISCEND study.

BACKGROUND AND AIMS: For patients with symptomatic, severe tricuspid regurgitation (TR), early results of transcatheter tricuspid valve (TV) intervention studies have shown significant improvements in functional status and quality of life associated with right-heart reverse remodelling. Longer-term follow-up is needed to confirm sustained improvements in these outcomes. METHODS: The prospective, single-arm, multicentre TRISCEND study enrolled 176 patients to evaluate the safety and performance of transcatheter TV replacement in patients with ≥moderate, symptomatic TR despite medical therapy. Major adverse events, reduction in TR grade and haemodynamic outcomes by echocardiography, and clinical, functional, and quality-of-life parameters are reported to one year. RESULTS: Enrolled patients were 71.0% female, mean age 78.7 years, 88.0% ≥ severe TR, and 75.4% New York Heart Association classes III-IV. Tricuspid regurgitation was reduced to ≤mild in 97.6% (P < .001), with increases in stroke volume (10.5 ± 16.8 mL, P < .001) and cardiac output (0.6 ± 1.2 L/min, P < .001). New York Heart Association class I or II was achieved in 93.3% (P < .001), Kansas City Cardiomyopathy Questionnaire score increased by 25.7 points (P < .001), and six-minute walk distance increased by 56.2 m (P < .001). All-cause mortality was 9.1%, and 10.2% of patients were hospitalized for heart failure. CONCLUSIONS: In an elderly, highly comorbid population with ≥moderate TR, patients receiving transfemoral EVOQUE transcatheter TV replacement had sustained TR reduction, significant increases in stroke volume and cardiac output, and high survival and low hospitalization rates with improved clinical, functional, and quality-of-life outcomes to one year. Funded by Edwards Lifesciences, TRISCEND ClinicalTrials.gov number, NCT04221490.

Tricuspid Valve Academic Research Consortium Definitions for Tricuspid Regurgitation and Trial Endpoints.

Interest in the pathophysiology, etiology, management, and outcomes of patients with tricuspid regurgitation (TR) has grown in the wake of multiple natural history studies showing progressively worse outcomes associated with increasing TR severity, even after adjusting for multiple comorbidities. Historically, isolated tricuspid valve surgery has been associated with high in-hospital mortality rates, leading to the development of transcatheter treatment options. The aim of this first Tricuspid Valve Academic Research Consortium document is to standardize definitions of disease etiology and severity, as well as endpoints for trials that aim to address the gaps in our knowledge related to identification and management of patients with TR. Standardizing endpoints for trials should provide consistency and enable meaningful comparisons between clinical trials. A second Tricuspid Valve Academic Research Consortium document will focus on further defining trial endpoints and will discuss trial design options.

Tricuspid Valve Academic Research Consortium Definitions for Tricuspid Regurgitation and Trial Endpoints.

Interest in the pathophysiology, etiology, management, and outcomes of patients with tricuspid regurgitation (TR) has grown in the wake of multiple natural history studies showing progressively worse outcomes associated with increasing TR severity, even after adjusting for multiple comorbidities. Historically, isolated tricuspid valve surgery has been associated with high in-hospital mortality rates, leading to the development of transcatheter treatment options. The aim of this first Tricuspid Valve Academic Research Consortium document is to standardize definitions of disease etiology and severity, as well as endpoints for trials that aim to address the gaps in our knowledge related to identification and management of patients with TR. Standardizing endpoints for trials should provide consistency and enable meaningful comparisons between clinical trials. A second Tricuspid Valve Academic Research Consortium document will focus on further defining trial endpoints and will discuss trial design options.

Tricuspid Valve Academic Research Consortium Definitions for Tricuspid Regurgitation and Trial Endpoints.

Interest in the pathophysiology, etiology, management, and outcomes of patients with tricuspid regurgitation (TR) has grown in the wake of multiple natural history studies showing progressively worse outcomes associated with increasing TR severity, even after adjusting for multiple comorbidities. Historically, isolated tricuspid valve surgery has been associated with high in-hospital mortality rates, leading to the development of transcatheter treatment options. The aim of this first Tricuspid Valve Academic Research Consortium document is to standardize definitions of disease etiology and severity, as well as endpoints for trials that aim to address the gaps in our knowledge related to identification and management of patients with TR. Standardizing endpoints for trials should provide consistency and enable meaningful comparisons between clinical trials. A second Tricuspid Valve Academic Research Consortium document will focus on further defining trial endpoints and will discuss trial design options.

Beyond Aortic Stenosis: Addressing the Challenges of Multivalvular Disease Assessment.

Aortic stenosis (AS) can often coexist with other valvular diseases or be combined with aortic regurgitation (AR), leading to unique pathophysiological conditions. The combination of affected valves can vary widely, resulting in a lack of standardized diagnostic or therapeutic approaches. Echocardiography is crucial in assessing patients with valvular heart disease (VHD), but careful consideration of the hemodynamic interactions between combined valvular defects is necessary. This is important as it may affect the reliability of commonly used echocardiographic parameters, making the diagnosis challenging. Therefore, a multimodality imaging approach, including computed tomography or cardiac magnetic resonance, is often not just beneficial but crucial. It represents the future of diagnostics in this intricate field due to its unprecedented capacity to quantify and comprehend valvular pathology. The absence of definitive data and guidelines for the therapeutic management of AS in the context of multiple valve lesions makes this condition particularly challenging. As a result, an individualized, case-by-case approach is necessary, guided primarily by the recommendations for the predominant valve lesion. This review aims to summarize the pathophysiology of AS in the context of multiple and mixed valve disease, with a focus on the hemodynamic implications, diagnostic challenges, and therapeutic options.