Polygenic Risk in Families With Spontaneous Coronary Artery Dissection.

Importance: Spontaneous coronary artery dissection (SCAD) is a poorly understood cause of acute coronary syndrome that predominantly affects women. Evidence to date suggests a complex genetic architecture, while a family history is reported for a minority of cases. Objective: To determine the contribution of rare and common genetic variants to SCAD risk in familial cases, the latter via the comparison of a polygenic risk score (PRS) with those with sporadic SCAD and healthy controls. Design, Setting, and Participants: This genetic association study analyzed families with SCAD, individuals with sporadic SCAD, and healthy controls. Genotyping was undertaken for all participants. Participants were recruited between 2017 and 2021. A PRS for SCAD was calculated for all participants. The presence of rare variants in genes associated with connective tissue disorders (CTD) was also assessed. Individuals with SCAD were recruited via social media or from a single medical center. A previously published control database of older healthy individuals was used. Data were analyzed from January 2022 to October 2023. Exposures: PRS for SCAD comprised of 7 single-nucleotide variants. Main Outcomes and Measures: Disease status (familial SCAD, sporadic SCAD, or healthy control) associated with PRS. Results: A total of 13 families with SCAD (27 affected and 12 unaffected individuals), 173 individuals with sporadic SCAD, and 1127 healthy controls were included. A total of 188 individuals with SCAD (94.0%) were female, including 25 of 27 with familial SCAD and 163 of 173 with sporadic SCAD; of 12 unaffected individuals from families with SCAD, 6 (50%) were female; and of 1127 healthy controls, 672 (59.6%) were female. Compared with healthy controls, the odds of being an affected family member or having sporadic SCAD was significantly associated with a SCAD PRS (where the odds ratio [OR] represents an increase in odds per 1-SD increase in PRS) (affected family member: OR, 2.14; 95% CI, 1.78-2.50; adjusted P = 1.96 × 10-4; sporadic SCAD: OR, 1.63; 95% CI, 1.37-1.89; adjusted P = 5.69 × 10-4). This association was not seen for unaffected family members (OR, 1.03; 95% CI, 0.46-1.61; adjusted P = .91) compared with controls. Further, those with familial SCAD were overrepresented in the top quintile of the control PRS distribution (OR, 3.70; 95% CI, 2.93-4.47; adjusted P = .001); those with sporadic SCAD showed a similar pattern (OR, 2.51; 95% CI, 1.98-3.04; adjusted P = .001). Affected individuals within a family did not share any rare deleterious variants in CTD-associated genes. Conclusions and Relevance: Extreme aggregation of common genetic risk appears to play a significant role in familial clustering of SCAD as well as in sporadic case predisposition, although further study is required.

Outcomes After Transcatheter Mitral Valve Replacement According to Regurgitation Etiology.

BACKGROUND: Whether transcatheter mitral valve replacement (TMVR) devices perform similarly with respect to the underlying mitral regurgitation (MR) etiology remains unknown. The aim of the present analysis was to assess outcomes of TMVR according to the MR underlying etiology among the CHoice of OptImal transCatheter trEatment for Mitral Insufficiency (CHOICE-MI) registry. METHODS: Of 746 patients, 229 patients (30.7%) underwent TMVR. The study population was subdivided according to primary, secondary, or mixed MR. Patients with mitral annular calcification were excluded. The primary study endpoint was a composite endpoint of all-cause mortality or hospitalization for heart failure at 1 year. Secondary study endpoints were all-cause and cardiovascular mortality at 1 year, New York Heart Association functional class, and residual MR, both at discharge and 1 year. RESULTS: The predominant MR etiology was secondary MR (58.4%), followed by primary MR (28.7%) and mixed MR (12.9%). Technical success and procedural mortality were similar according to MR etiology. Discharge echocardiography revealed residual MR 2+ in 11.3%, 3.7%, and 5.3% of patients with primary, secondary, and mixed MR, respectively (P = .1). MR elimination was similar in all groups up to the 1-year follow-up. There was no difference in terms of primary combined outcome occurrence according to MR etiology. One-year all-cause mortality was reported in 28.8%, 24.2%, and 32.1% of patients with primary, secondary, and mixed MR, respectively (P = .07). CONCLUSIONS: In our study we did not find differences in short-term and 1-year outcomes after TMVR according to MR etiology.

Machine learning prediction of progressive subclinical myocardial dysfunction in moderate aortic stenosis.

Background: Moderate severity aortic stenosis (AS) is poorly understood, is associated with subclinical myocardial dysfunction, and can lead to adverse outcome rates that are comparable to severe AS. Factors associated with progressive myocardial dysfunction in moderate AS are not well described. Artificial neural networks (ANNs) can identify patterns, inform clinical risk, and identify features of importance in clinical datasets. Methods: We conducted ANN analyses on longitudinal echocardiographic data collected from 66 individuals with moderate AS who underwent serial echocardiography at our institution. Image phenotyping involved left ventricular global longitudinal strain (GLS) and valve stenosis severity (including energetics) analysis. ANNs were constructed using two multilayer perceptron models. The first model was developed to predict change in GLS from baseline echocardiography alone and the second to predict change in GLS using data from baseline and serial echocardiography. ANNs used a single hidden layer architecture and a 70%:30% training/testing split. Results: Over a median follow-up interval of 1.3 years, change in GLS (≤ or >median change) could be predicted with accuracy rates of 95% in training and 93% in testing using ANN with inputs from baseline echocardiogram data alone (AUC: 0.997). The four most important predictive baseline features (reported as normalized % importance relative to most important feature) were peak gradient (100%), energy loss (93%), GLS (80%), and DI < 0.25 (50%). When a further model was run including inputs from both baseline and serial echocardiography (AUC 0.844), the top four features of importance were change in dimensionless index between index and follow-up studies (100%), baseline peak gradient (79%), baseline energy loss (72%), and baseline GLS (63%). Conclusions: Artificial neural networks can predict progressive subclinical myocardial dysfunction with high accuracy in moderate AS and identify features of importance. Key features associated with classifying progression in subclinical myocardial dysfunction included peak gradient, dimensionless index, GLS, and hydraulic load (energy loss), suggesting that these features should be closely evaluated and monitored in AS.

Transcatheter Mitral Valve Replacement Versus Medical Therapy for Secondary Mitral Regurgitation: A Propensity Score-Matched Comparison.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) is an emerging therapeutic alternative for patients with secondary mitral regurgitation (MR). Outcomes of TMVR versus guideline-directed medical therapy (GDMT) have not been investigated for this population. This study aimed to compare clinical outcomes of patients with secondary MR undergoing TMVR versus GDMT alone. METHODS: The CHOICE-MI registry (Choice of Optimal Transcatheter Treatment for Mitral Insufficiency) included patients with MR undergoing TMVR using dedicated devices. Patients with MR pathogeneses other than secondary MR were excluded. Patients treated with GDMT alone were derived from the control arm of the COAPT trial (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation). We compared outcomes between the TMVR and GDMT groups, using propensity score matching to adjust for baseline differences. RESULTS: After propensity score matching, 97 patient pairs undergoing TMVR (72.9±8.7 years; 60.8% men; transapical access, 91.8%) versus GDMT (73.1±11.0 years; 59.8% men) were compared. At 1 and 2 years, residual MR was ≤1+ in all patients of the TMVR group compared with 6.9% and 7.7%, respectively, in those receiving GDMT alone (both P<0.001). The 2-year rate of heart failure hospitalization was significantly lower in the TMVR group (32.8% versus 54.4%; hazard ratio, 0.59 [95% CI, 0.35-0.99]; P=0.04). Among survivors, a higher proportion of patients were in the New York Heart Association functional class I or II in the TMVR group at 1 year (78.2% versus 59.7%; P=0.03) and at 2 years (77.8% versus 53.2%; P=0.09). Two-year mortality was similar in the 2 groups (TMVR versus GDMT, 36.8% versus 40.8%; hazard ratio, 1.01 [95% CI, 0.62-1.64]; P=0.98). CONCLUSIONS: In this observational comparison, over 2-year follow-up, TMVR using mostly transapical devices in patients with secondary MR was associated with significant reduction of MR, symptomatic improvement, less frequent hospitalizations for heart failure, and similar mortality compared with GDMT. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT04688190 (CHOICE-MI) and NCT01626079 (COAPT).

Genome-wide association meta-analysis of spontaneous coronary artery dissection identifies risk variants and genes related to artery integrity and tissue-mediated coagulation.

Spontaneous coronary artery dissection (SCAD) is an understudied cause of myocardial infarction primarily affecting women. It is not known to what extent SCAD is genetically distinct from other cardiovascular diseases, including atherosclerotic coronary artery disease (CAD). Here we present a genome-wide association meta-analysis (1,917 cases and 9,292 controls) identifying 16 risk loci for SCAD. Integrative functional annotations prioritized genes that are likely to be regulated in vascular smooth muscle cells and artery fibroblasts and implicated in extracellular matrix biology. One locus containing the tissue factor gene F3, which is involved in blood coagulation cascade initiation, appears to be specific for SCAD risk. Several associated variants have diametrically opposite associations with CAD, suggesting that shared biological processes contribute to both diseases, but through different mechanisms. We also infer a causal role for high blood pressure in SCAD. Our findings provide novel pathophysiological insights involving arterial integrity and tissue-mediated coagulation in SCAD and set the stage for future specific therapeutics and preventions.

Transcatheter mitral valve replacement or repair for secondary mitral regurgitation: a propensity score-matched analysis.

AIMS: This study aimed to compare outcomes after transcatheter mitral valve replacement (TMVR) and mitral valve transcatheter edge-to-edge repair (M-TEER) for the treatment of secondary mitral regurgitation (SMR). METHODS AND RESULTS: The CHOICE-MI registry included 262 patients with SMR treated with TMVR between 2014 and 2022. The EuroSMR registry included 1065 patients with SMR treated with M-TEER between 2014 and 2019. Propensity score (PS) matching was performed for 12 demographic, clinical and echocardiographic parameters. Echocardiographic, functional and clinical outcomes out to 1 year were compared in the matched cohorts. After PS matching, 235 TMVR patients (75.5 years [70.0, 80.0], 60.2% male, EuroSCORE II 6.3% [interquartile range 3.8, 12.4]) were compared to 411 M-TEER patients (76.7 years [70.1, 80.5], 59.0% male, EuroSCORE II 6.7% [3.9, 12.4]). All-cause mortality was 6.8% after TMVR and 3.8% after M-TEER at 30 days (p = 0.11), and 25.8% after TMVR and 18.9% after M-TEER at 1 year (p = 0.056). No differences in mortality after 1 year were found between both groups in a 30-day landmark analysis (TMVR: 20.4%, M-TEER: 15.8%, p = 0.21). Compared to M-TEER, TMVR resulted in more effective mitral regurgitation (MR) reduction (residual MR ≤1+ at discharge for TMVR vs. M-TEER: 95.8% vs. 68.8%, p < 0.001), and superior symptomatic improvement (New York Heart Association class ≤II at 1 year: 77.8% vs. 64.3%, p = 0.015). CONCLUSION: In this PS-matched comparison between TMVR and M-TEER in patients with severe SMR, TMVR was associated with superior reduction of MR and superior symptomatic improvement. While post-procedural mortality tended to be higher after TMVR, no significant differences in mortality were found beyond 30 days.

Peri-procedural management of transcatheter mitral valve replacement in patients with heart failure.

Over the past decade, transcatheter mitral valve replacement (TMVR) technologies have evolved with the objective of improving outcomes for patients with severe mitral regurgitation (MR) deemed unsuitable for conventional mitral valve surgery. Although the safety and efficacy of transcatheter edge-to-edge mitral valve repair (TEER) is well-established, there is a sense amongst innovators that a major advantage of TMVR may be to offer a more complete solution for the correction of MR in patients whose complex anatomy means that the likelihood of achieving grade 0 or 1 MR with TEER is low. However, abrupt correction of MR in a poorly prepared left ventricle poses a number of unique haemodynamic challenges, particularly when sudden elimination of regurgitant flow causes a relative increase in left ventricular (LV) afterload. Rapid reduction in LV cavity size following MR elimination may itself result in relative LV outflow tract obstruction (LVOTO), irrespective of the intrinsic risk of LVOTO associated with TMVR. Nevertheless, TMVR on a beating heart affords the opportunity to study real-time invasive cardiac indices in high-risk patients with acute reversal of severe MR.

Pulsatile energy consumption as a surrogate marker for vascular afterload improves with time post transcatheter aortic valve replacement in patients with aortic stenosis.

The effect of arterial stiffening on elevated pulsatile left ventricular afterload patients with aortic stenosis (AS) is pronounced beyond systemic hypertension. Circulatory afterload pulsatile efficiency (CAPE) is a marker of vascular function, defined as the ratio of steady state energy consumption (SEC) to maintain systemic circulation and pulsatile energy consumption (PEC). Twenty patients aged 80 ± 7 years were assessed at baseline and a median of 60 days post transcatheter aortic valve replacement (TAVR), with pulsatile vascular load calculated using simultaneous radial applanation tonometry derived aortic pressure and cardiac magnetic resonance phase-contrast imaging derived ascending aortic flow. Eight out of 20 patients had a reduction in PEC post TAVR, and the reduction of PEC correlated strongly with the number of days post TAVR (R = 0.62, P < 0.01). Patients assessed within the 100 days of TAVR had a rise in their PEC when compared to baseline (0.19 ± 0.09 vs 0.14 ± 0.08 W, P = 0.04). Baseline PEC correlated moderately with baseline SEC (R = 0.49, P = 0.03), and a high baseline PEC was predictive of post TAVR PEC reduction (R = 0.54, P =0.01). Overall, no significant differences were found between baseline and post TAVR for systolic aortic pressure (131 ± 20 vs 131 ± 20 mmHg), systemic vascular resistance (1894 ± 493 vs 2015 ± 519 dynes.s/cm5), aortic valve ejection time (337 ± 22 vs 324 ± 34 ms) or aortic characteristic impedance (120 ± 48 vs 107 ± 41 dynes.s/cm5). Improved flow profiles after TAVR likely unmask the true vascular properties by altering ventriculo-valvulo-arterial coupling, leading to downstream vascular remodelling secondary to flow conditioning, and results in eventual improvement of pulsatile afterload as reflected by our proposed index of CAPE.

Fluid structure computational model of simulating mitral valve motion in a contracting left ventricle.

BACKGROUND: Fluid structure interaction simulations h hold promise in studying normal and abnormal cardiac function, including the effect of fluid dynamics on mitral valve (MV) leaflet motion. The goal of this study was to develop a 3D fluid structure interaction computational model to simulate bileaflet MV when interacting with blood motion in left ventricle (LV). METHODS: The model consists of ideal geometric-shaped MV leaflets and the LV, with MV dimensions based on human anatomical measurements. An experimentally-based hyperelastic isotropic material was used to model the mechanical behaviour of the MV leaflets, with chordae tendineae and papillary muscle tips also incorporated. LV myocardial tissue was prescribed using a transverse isotropic hyperelastic formulation. Incompressible Navier-Stokes fluid formulations were used to govern the blood motion, and the Arbitrary Lagrangian Eulerian (ALE) method was employed to determine the mesh deformation of the fluid and solid domains due to trans-valvular pressure on MV boundaries and the resulting leaflet movement. RESULTS: The LV-MV generic model was able to reproduce physiological MV leaflet opening and closing profiles resulting from the time-varying atrial and ventricular pressures, as well as simulating normal and prolapsed MV states. Additionally, the model was able to simulate blood flow patterns after insertion of a prosthetic MV with and without left ventricular outflow tract flow obstruction. In the MV-LV normal model, the regurgitant blood flow fraction was 10.1 %, with no abnormality in cardiac function according to the mitral regurgitation severity grades reported by the American Society of Echocardiography. CONCLUSION: Our simulation approach provides insights into intraventricular fluid dynamics in a contracting LV with normal and prolapsed MV function, as well as aiding in the understanding of possible complications after transcatheter MV implantation prior to clinical trials.

Extracorporeal Membrane Oxygenation-Supported Transcatheter Mitral Valve-in-Valve Replacement and Paravalvular Plugging for Critical Prosthetic Mitral Stenosis.

We present the case of a patient with rapidly progressive bioprosthetic mitral valve stenosis in the setting of end-stage renal failure. Critical valve stenosis led to cardiogenic shock requiring full hemodynamic support. Emergent extracorporeal membrane oxygenation-supported transcatheter mitral valve-in-valve implantation was successfully undertaken as a life-saving measure with an excellent final result. (Level of Difficulty: Advanced.).

Exploring the Genetic Architecture of Spontaneous Coronary Artery Dissection Using Whole-Genome Sequencing.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndrome that predominantly affects women. Its pathophysiology remains unclear but connective tissue disorders (CTD) and other vasculopathies have been observed in many SCAD patients. A genetic component for SCAD is increasingly appreciated, although few genes have been robustly implicated. We sought to clarify the genetic cause of SCAD using targeted and genome-wide methods in a cohort of sporadic cases to identify both common and rare disease-associated variants. METHODS: A cohort of 91 unrelated sporadic SCAD cases was investigated for rare, deleterious variants in genes associated with either SCAD or CTD, while new candidate genes were sought using rare variant collapsing analysis and identification of novel loss-of-function variants in genes intolerant to such variation. Finally, 2 SCAD polygenic risk scores were applied to assess the contribution of common variants. RESULTS: We identified 10 cases with at least one rare, likely disease-causing variant in CTD-associated genes, although only one had a CTD phenotype. No genes were significantly associated with SCAD from genome-wide collapsing analysis, however, enrichment for TGF (transforming growth factor)-ß signaling pathway genes was found with analysis of 24 genes harboring novel loss-of-function variants. Both polygenic risk scores demonstrated that sporadic SCAD cases have a significantly elevated genetic SCAD risk compared with controls. CONCLUSIONS: SCAD shares some genetic overlap with CTD, even in the absence of any major CTD phenotype. Consistent with a complex genetic architecture, SCAD patients also have a higher burden of common variants than controls.

Characteristics and outcomes of patients screened for transcatheter mitral valve implantation: 1-year results from the CHOICE-MI registry.

AIMS: Transcatheter mitral valve implantation (TMVI) represents a novel treatment option for patients with mitral regurgitation (MR) unsuitable for established therapies. The CHOICE-MI registry aimed to investigate outcomes of patients undergoing screening for TMVI. METHODS AND RESULTS: From May 2014 to March 2021, patients with MR considered suboptimal candidates for transcatheter edge-to-edge repair (TEER) and at high risk for mitral valve surgery underwent TMVI screening at 26 centres. Characteristics and outcomes were investigated for patients undergoing TMVI and for TMVI-ineligible patients referred to bailout-TEER, high-risk surgery or medical therapy (MT). The primary composite endpoint was all-cause mortality or heart failure hospitalization after 1 year. Among 746 patients included (78.5 years, interquartile range [IQR] 72.0-83.0, EuroSCORE II 4.7% [IQR 2.7-9.7]), 229 patients (30.7%) underwent TMVI with 10 different dedicated devices. At 1 year, residual MR ≤1+ was present in 95.2% and the primary endpoint occurred in 39.2% of patients treated with TMVI. In TMVI-ineligible patients (n = 517, 69.3%), rates of residual MR ≤1+ were 37.2%, 100.0% and 2.4% after bailout-TEER, high-risk surgery and MT, respectively. The primary endpoint at 1 year occurred in 28.8% of patients referred to bailout-TEER, in 42.9% of patients undergoing high-risk surgery and in 47.9% of patients remaining on MT. CONCLUSION: This registry included the largest number of patients treated with TMVI to date. TMVI with 10 dedicated devices resulted in predictable MR elimination and sustained functional improvement at 1 year. In TMVI-ineligible patients, bailout-TEER and high-risk surgery represented reasonable alternatives, while MT was associated with poor clinical and functional outcomes.

Transapical Transcatheter Mitral Valve Implantation in Heart Failure: Haemodynamic Challenges for a New Frontier.

Secondary mitral regurgitation (MR) and heart failure are mutually dependent. Secondary MR occurs as a consequence of heart failure in patients with impaired left ventricular (LV) function, decreasing cardiac efficiency, accelerating a decline in contractility and worsening the already dismal prognosis of these patients. Advances in transcatheter techniques have now given promise to improved survival, outcomes, and quality of life for patients with advanced heart failure and secondary MR. Although transcatheter edge-to-edge repair is well established, transapical transcatheter mitral valve implantation (TMVI) may represent a more durable solution for correction of secondary MR without the need for cardiopulmonary bypass. Correction of MR, however, is thought to acutely increase LV afterload due to the elimination of low afterload regurgitant flow. In high-risk patients, this may cause acute decompensated heart failure. Off-pump TMVI on a beating heart poses a number of unique challenges, but also the opportunity to study invasive haemodynamic indices in high-risk heart failure patients for the first time. In the following discussion, we review the acute haemodynamic changes during off-pump TMVI in patients with heart failure in order to better guide optimal patient selection and management.

2-Year Outcomes of Transcatheter Mitral Valve Replacement in Patients With Severe Symptomatic Mitral Regurgitation.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) is feasible for selected patients with severe mitral regurgitation (MR) who are poor candidates for valve surgery. Intermediate-term to long-term TMVR outcomes have not been reported. OBJECTIVES: This study sought to evaluate the safety and effectiveness through 2-year follow-up of TMVR in high-surgical-risk patients with severe MR. METHODS: The first 100 patients enrolled in the Expanded Clinical Study of the Tendyne Mitral Valve System, an open-label, nonrandomized, prospective study of transapical TMVR, were followed for 2 years. RESULTS: The patients (aged 74.7 ± 8.0 years, 69.0% male) had symptomatic (66.0% New York Heart Association [NYHA] functional class III or IV) grade 3+ or 4+ MR that was secondary or mixed in 89 (89.0%). Prostheses were successfully implanted in 97 (97.0%) patients. At 2 years, all-cause mortality was 39.0%; 17 (43.6%) of 39 deaths occurred during the first 90 days. Heart failure hospitalization (HFH) fell from 1.30 events per year preprocedure to 0.51 per year in the 2 years post-TMVR (P < 0.0001). At 2 years, 93.2% of surviving patients had no MR. No patient had >1+ MR. The improvement in symptoms at 1 year (88.5% NYHA functional class I or II) was sustained to 2 years (81.6% NYHA functional class I or II). Among survivors, the left ventricular ejection fraction was 45.6 ± 9.4% at baseline and 39.8 ± 9.5% at 2 years (P = 0.0012). Estimated right ventricular systolic pressure decreased from 47.6 ± 8.6 mm Hg to 32.5 ± 10.4 mm Hg (P < 0.005). CONCLUSIONS: In this study, the impact of TMVR on severity of MR, reduction in HFH rate, and improvement in symptoms was sustained through 2 years. All-cause mortality and the need for HFH was highest in the first 3 months postprocedure. (Expanded Clinical Study of the Tendyne Mitral Valve System; NCT02321514).

2021 CSANZ and ANZSCTS Position Statement on the Operator and Institutional Requirements for a Transcatheter Aortic Valve Implantation (TAVI) Program in Australia.

This document establishes the minimum standard for accreditation of institutions and operators as endorsed by the Cardiac Society of Australia and New Zealand (CSANZ) and the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS). The original Joint Society Position Statement was ratified in August 2014. This 2021 update replaces the original and serves as a consensus within which the Conjoint Committee for Trancatheter Aortic Valve Implantation (TAVI) Accreditation will function, as recommended by Medical Services Advisory Committee (MSAC) Determination for TAVI. This is not a Guideline Statement but takes into consideration regional, legislative, and health system factors important to establishing requirements for TAVI accreditation in Australia.

Operator and Institutional Requirements for Transcatheter Mitral Valve Therapies in Australia: a CSANZ and ANZSCTS Position Statement.

This expert Position Statement is a description of the requirements for Accreditation for transcatheter mitral valve therapy (TMVT) in Australia. The requirements include the need for a multidisciplinary Heart Team review of individual cases, mandatory reporting of outcome data to a national TMVT Registry, and accreditation of individuals and institutions by the Conjoint Accreditation Committee, the assigned accreditation authority.

Ageing, Hypertension and Aortic Valve Stenosis: A Conscious Uncoupling.

Aortic valve stenosis (AS) is no longer considered to be a disease of fixed left ventricular (LV) afterload (due to an obstructive valve), but rather, functions as a series circuit with important contributions from both the valve and ageing vasculature. Patients with AS are frequently elderly, with hypertension and a markedly remodelled aorta. The arterial component is sizable, and yet, the contribution of ventricular afterload has been difficult to determine. Arterial stiffening increases the speed of propagation of the blood pressure wave along the central arteries (estimated as the pulse wave velocity), which results in an earlier return of reflected waves. The effect is to augment blood pressure in the proximal aorta during systole, increasing the central pulse pressure and, in turn, placing even greater afterload on the heart. Elevated global LV afterload is known to have adverse consequences on LV remodelling, function and survival in patients with AS. Consequently, there is renewed focus on methods to estimate the relative contributions of local versus global changes in arterial mechanics and valvular haemodynamics in patients with AS. We present a review on existing and upcoming methods to quantify valvulo-arterial impedance and thereby global LV load in patients with AS.

A novel method to assess valvulo-arterial load in patients with aortic valve stenosis.

INTRODUCTION: Ventricular function in elderly patients with aortic stenosis is impeded both by restricted aortic flow and arterial stiffening. A number of patients continue to have exertional intolerance after relief of aortic valvular obstruction due to unrecognized ventriculo-arterial coupling mismatch. HYPOTHESIS: Quantification of valvulo-arterial load (VAL), using a simultaneous applanation tonometry/cardiac magnetic resonance (CMR) technique, can accurately assess the relative contributions of aortic stiffness and valve gradient in older patients with aortic stenosis. METHODS: Elderly patients with aortic stenosis underwent a simultaneous applanation tonometry/CMR protocol. CMR provided left ventricular volume and aortic flow simultaneously with radial applanation tonometry pressure acquisition. Central aortic pressure was derived by transformation of the radial applanation tonometry waveform. VAL was determined as the relationship of derived aortic pressure to CMR aortic flow in frequency domain (central illustration). RESULTS: Twenty patients (age 80 ±â€Š9 years; 12 males; blood pressure 140/75 ±â€Š20 mmHg) with aortic stenosis on transthoracic echocardiogram (16 severe; mean gradient 45 ±â€Š16 mmHg; aortic valve area 0.8 ±â€Š0.2 cm2) were enrolled. Derived aortic pressure and flow waveforms correlated well with invasive data. Increased VAL was significantly associated with advanced age (P = 0.04) and raised SBP (P < 0.01), irrespective of aortic stenosis severity. CONCLUSION: Difficulties in the measurement and accuracy of ventriculo-arterial coupling means that it is not routinely measured in patients with aortic stenosis. We describe a new noninvasive index that provides an accurate assessment of valvular and arterial load on the left ventricle. VAL may help detect those at risk of ventriculo-arterial coupling mismatch and assist in selection of those most likely to benefit from an invasive procedure.