Real-Time Magnetic Resonance Imaging-Guided Transarterial Aortic Valve Implantation In-Vivo Evaluation in Swine

Real-time magnetic resonance imaging (rtMRI) is considered attractive for guiding transarterial aortic valve implantation (TAVI). Compared with X-ray fluoroscopy, rtMRI offers unrestricted scan plane orientation and an unsurpassed soft-tissue contrast with simultaneous device visualization, potentially allowing enhanced positioning accuracy together with online monitoring of cardiac function and immediate detection of complications. Additionally, MRI offers noninvasive assessment of cardiovascular anatomy and function for preinterventional screening as well as immediate morphologic and functional assessment of the implanted prothesis and may, thus, be envisioned as a single comprehensive imaging modality for TAVI. We, therefore, sought to assess the preclinical feasibility of entirely rtMRI-guided TAVI in a swine model (female domestic pigs weighing 70.5 to 86.5 kg) using the original CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis without alterations in conjunction with a modified, MRI-compatible delivery device (1).

rtMRI-guided transfemoral (n = 2) and transsubclavian (n = 6) TAVI was performed in a 1.5-T whole-body MRI scanner (Magnetom Avanto, Siemens Healthcare Sector, Erlangen, Germany). Conventional x-ray fluoroscopy and angiography were performed for comparison. After pre-interventional evaluation using standard steady-state free-precession imaging with electrocardiographic gating and time-resolved retrospective image reconstruction (cine-TrueFISP retro) (TR, 40 ms; TE, 1.1 ms; flip angle, 62°; FOV, 380 x 330 mm2; matrix, 192 x 168; slice thickness, 6 mm; bandwidth, 930 Hz/pixel; image acquisition time, 15 s for a single slice acquired over 20 phases of the cardiac R-R interval) and electrocardiography-triggered, flow-sensitive, phase-contrast sequences (TR, 62 ms; TE, 3.5 ms; flip angle, 30°; FOV, 320 x 220 mm2; matrix, 192 x 132; bandwidth, 555 Hz/pixel; acquisition time, 1 min 52 s; velocity encoding value, 100 cm/s), TAVI was performed using rtMRI fluoroscopy based on a commercially available interactive real-time projection reconstruction TrueFISP sequence with radial k-space filling during free breathing and without cardiac triggering that was modified to achieve a frame rate of 7 frames per second (TR, 3.0 ms; TE, 1.5 ms; flip angle, 70°; FOV, 360 x 360 mm2; matrix, 192 x 192; bandwidth, 1530 Hz/pixel; slice thickness, 6 mm). Images were displayed without delay inside the scanner room and could be adapted interactively according to the operator’s (P.K.) needs while the sequence was running. After TAVI, real-time TrueFISP, cine-TrueFISP retro, and flow-sensitive phase-contrast sequences were used to verify procedural success. Autopsies were performed to validate MRI findings.

Three-point localizer sequences allowed for rapid detection (11 ± 3 min) of all scan planes required for preinterventional evaluation, procedural guidance, and post-procedural validation. High-resolution TrueFISP retro sequences enabled detailed visualization of all procedurally relevant anatomic landmarks and allowed precise measurements (aortic annulus diameter in long axis, 17 ± 3 mm; aortic arch diameter, 21 ± 4 mm; distance from aortic annulus to left and right coronary ostium, 9 ± 3 and 10 ± 2 mm; access vessel diameter, 6.9 ± 1.2 mm) in good accordance with measurements on previous angiographic images (mean error, 0.4 ± 0.3 mm; p = NS) and during autopsy (mean error, 0.5 ± 0.2 mm; p = NS).

Passive device visualization using real-time TrueFISP sequences provided reliable imaging guidance during TAVI superior to fluoroscopy. Mild susceptibility artifacts confined to the loaded stent valve enabled adequate determination of the position of stent valve and delivery system in relation to the surrounding anatomy without undue image distortion, allowing a precise, real-time anatomic orientation during device navigation through the vasculature, aortic valve passage, positioning and deployment of the prosthesis, and catheter withdrawal.

In 6 of 8 animals, an oversized 26-mm CoreValve prosthesis was successfully placed across the aortic annulus without dislocation, coronary artery obstruction, or impairment of the mitral valve, as confirmed by autopsy (rtMRI acquisition time, 4 ± 2 min) (Fig. 1). However, 2 implant failures occurred. The first was a result of unsuccessful aortic arch passage due to insufficient support by the initially used MRI-compatible, soft polymer guidewire and led to a controlled deployment of the stent valve in the thoracic aorta, which is sometimes required in clinical application when the prosthesis dislocates into the ascending aorta during deployment. As a consequence, we continued our experiments without guidewire support and focused on the straighter transsubclavian access route. The second implant failure occurred due to perforation of the left ventricular apex caused by the delivery device, which was inadvertently pushed with too much force, this complication being immediately detected by rtMRI. Both cases indicate that rtMRI might improve both precision and safety of the TAVI procedure.

Postprocedural TrueFISP retro sequences allowed precise structural evaluation of the procedural result in good accordance with autopsy findings. Flow-sensitive, electrocardiography-triggered, phase-contrast sequences with imaging planes placed approximately 1 cm below and above the nitinol stent frame confirmed good systolic transvalvular blood flow without diastolic regurgitation. The current study demonstrates the preclinical feasibility of entirely MRI-guided TAVI. As a single imaging modality, MRI offered comprehensive diagnostic evaluation of the relevant cardiac and vascular anatomy for adequate interventional planning, real-time procedural guidance with excellent anatomic orientation, immediate evaluation of procedure-related complications, and post-interventional validation of treatment success with a total procedure time of 61 ± 13 min. Complementary to reduction of radiation exposure and nephrotoxic contrast media, rtMRI guidance, therefore, provides clinically relevant advantages over conventional X-ray-fluoroscopy and warrants further attention. These advantages should encourage future efforts to translate rtMRI-guided TAVI into clinical application using commercial but modified or entirely novel devices (2,3) and to overcome remaining obstacles such as the development of suitable, MRI-compatible guidewires.

PMID: 22222083

Multicenter Assessment of the Reproducibility of Volumetric Radiofrequency-Based Intravascular Ultrasound Measurements in Coronary Lesions that Were Consecutively Stented

OBJECTIVES: To assess in a multicenter design the between-center reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computer-assisted contour detection system in coronary lesions that were consecutively stented.

METHODS: 4 European IVUS centers performed independent analyses (in total 8,052 cross-sectional analyses) to obtain volumetric data of 40 coronarysegments (length 20.0 ± 0.3 mm) from target lesions prior to percutaneous intervention that were performed in the setting of stable (65%) or unstable angina pectoris (35%).

RESULTS: Geometric and compositional VH-IVUS measurements were highly correlated for the different comparisons. Overall intraclass correlation for vessel, lumen, plaque volume and plaque burden was 0.99, 0.92, 0.96, and 0.83, respectively; for fibrous, fibro-lipidic, necrotic core and calcified volumes overall intraclass correlation was 0.96, 0.94, 0.98, and 0.99, respectively. Nevertheless, significant differences for both geometrical and compositional measurements were seen. Of the plaque components, fibrous tissue and necrotic core showed on average the highest measurement reproducibility.

CONCLUSIONS: A central analysis for VH-IVUS multicenter studies of lesions prior to PCI should be pursued. Moreover, it may be problematical to pool VH-IVUS data of individual trials analyzed by independent centers.

PMID: 22246064

Natural History of Stent Edge Dissection, Tissue Protrusion and Incomplete Stent Apposition Detectable Only on Optical Coherence Tomography After Stent Implantation

OBJECTIVES: The clinical impact of stent edge dissection, tissue protrusion, and incomplete stent apposition (ISA) after stent implantation, detectable only on optical coherence tomography (OCT), is still unknown because the natural course has not been investigated.

METHODS: All consecutive patients with angina pectoris in whom both intravascular ultrasound (IVUS) and OCT were performed immediately after stenting and at follow-up were included in the present study. The natural history of OCT-detected stent edge dissection, tissue protrusion, and ISA during follow-up was investigated.

RESULTS: A total of 36 patients with 39 lesions was analyzed. At baseline, OCT showed 12 stent edge dissections, 25 tissue protrusions, and 8 ISAs, whereas IVUS demonstrated 6 stent edge dissections, 5 tissue protrusions, and 3 ISAs. All IVUS findings were clearly visualized on OCT. The maximum length of dissection flap and depth of ISA visualized on OCT were significantly shorter than those visualized on IVUS. Maximum length of tissue protrusion tended to be smaller on OCT than on IVUS. At follow-up (median 188 days), all findings noted on OCT were healed or resolved without any restenosis or thrombus formation.

CONCLUSIONS: Acute findings after stenting, such as edge dissection, tissue protrusion, and ISA, detectable only on OCT, tended to be smaller than those seen on both OCT and IVUS. The majority of OCT-detected acute findings resolved completely at follow-up.

PMID: 22251751

Long-Term Follow-Up After Fractional Flow Reserve-Guided Treatment Strategy in Patients With an Isolated Proximal Left Anterior Descending Coronary Artery Stenosis

OBJECTIVES: This study sought to evaluate the long-term clinical outcome of patients with an angiographically intermediate left anterior descending coronary artery (LAD) stenosis in whom the revascularization strategy was based on fractional flow reserve (FFR). When revascularization is based mainly on angiographic guidance, a number of hemodynamically nonsignificant stenoses will be revascularized.

METHODS: In 730 patients with a 30% to 70% isolated stenosis in the proximal LAD and no significant valvular disease, FFR measurements were obtained to guide treatment strategy. When FFR was ≥ 0.80, the patients (n = 564) were treated medically (medical group); when FFR was <0.80, the patients (n = 166) underwent a revascularization procedure (revascularization group; 13% coronary artery bypass graft surgery and 87% percutaneous coronary intervention). A 100% long-term clinical follow-up (median follow-up: 40 months) was obtained. The 5-year survival of the medical group was compared with that of a reference population. For each patient, 4 controls were selected from an age- and sex-matched control population.

RESULTS: The 5-year survival estimate was 92.9% in the medical group versus 89.6% in the controls (p = 0.74). The mean diameter stenosis was significantly smaller in the medical than in the revascularization group (39 ± 14% vs. 54 ± 13%, p < 0.0001), but there was a large overlap between both groups. The 5-year event-free survival estimates (death, myocardial infarction, and target vessel revascularization) were 89.7% and 68.5%, respectively (p < 0.0001).

CONCLUSIONS: Medical treatment of patients with a hemodynamically nonsignificant stenosis (FFR ≥ 0.80) in the proximal LAD is associated with an excellent long-term clinical outcome with survival at 5 years similar to an age- and sex-matched control population.

PMID: 22035875

Computed Tomography Stress Myocardial Perfusion Imaging in Patients Considered for Revascularization: A Comparison With Fractional Flow Reserve

PMID: 21810860

Thin-Cap Fibroatheroma and Microchannel Findings in Optical Coherence Tomography Correlate With Subsequent Progression of Coronary Atheromatous Plaques

OBJECTIVES:  Morphological characteristics of non-significant coronary plaques (NSCPs) that develop rapid progression have not been fully elucidated. The aim of this study was to clarify the morphological characteristics of NSCPs in patients with coronary artery disease (CAD) using intravascular optical coherence tomography (OCT).

METHODS:  Fifty-three consecutive CAD patients undergoing percutaneous coronary intervention were enrolled and 69 NSCPs (per cent diameter stenosis <50%) were identified on baseline angiogram. Baseline characteristics of NSCPs were evaluated by OCT, and patients were followed-up prospectively. At the second coronary angiography, the baseline OCT characteristics and plaque progression were correlated.

RESULTS: During the 7-month follow-up period, 13 NSCPs showed angiographic progression and 56 NSCPs did not. Baseline minimum lumen diameter and diametric stenosis were similar between NSCPs with and without progression. Compared with NSCPs without progression, those with progression showed a significantly higher incidence of intimal laceration (61.5 vs. 8.9%, P < 0.01), microchannel (76.9 vs. 14.3%, P < 0.01), lipid pools (100 vs. 60.7%, P = 0.02), thin-cap fibroatheroma (TCFA) (76.9 vs. 14.3%, P < 0.01), macrophage images (61.5 vs. 14.3%, P < 0.01), and intraluminal thrombi (30.8 vs. 1.8%, P < 0.01). Univariate regression analysis showed that TCFA and microchannel images showed high correlation with subsequent luminal progression [odds ratio (OR): 20.0, P < 0.01 and OR: 20.0, P < 0.01, respectively].

CONCLUSIONS: Optical coherence tomography-based complex characteristics of TCFA and microchannel were the potential predictors of subsequent progression of NSCPs in patients with CAD.

PMID: 21831910

Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography for Diagnosis of Coronary Heart Disease (CE-MARC): A Prospective Trial

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Effect of Two Intensive Statin Regimens on Progression of Coronary Disease

OBJECTIVES: Statins reduce adverse cardiovascular outcomes and slow the progression of coronary atherosclerosis in proportion to their ability to reduce low-density lipoprotein (LDL) cholesterol. However, few studies have either assessed the ability of intensive statin treatments to achieve disease regression or compared alternative approaches to maximal statin administration.

METHODS: We performed serial intravascular ultrasonography in 1039 patients with coronary disease, at baseline and after 104 weeks of treatment with either atorvastatin, 80 mg daily, or rosuvastatin, 40 mg daily, to compare the effect of these two intensive statin regimens on the progression of coronary atherosclerosis, as well as to assess their safety and side-effect profiles.

RESULTS: After 104 weeks of therapy, the rosuvastatin group had lower levels of LDL cholesterol than the atorvastatin group (62.6 vs. 70.2 mg per deciliter [1.62 vs. 1.82 mmol per liter], P<0.001), and higher levels of high-density lipoprotein (HDL) cholesterol (50.4 vs. 48.6 mg per deciliter [1.30 vs. 1.26 mmol per liter], P=0.01). The primary efficacy end point, percent atheroma volume (PAV), decreased by 0.99% (95% confidence interval [CI], -1.19 to -0.63) with atorvastatin and by 1.22% (95% CI, -1.52 to -0.90) with rosuvastatin (P=0.17). The effect on the secondary efficacy end point, normalized total atheroma volume (TAV), was more favorable with rosuvastatin than with atorvastatin: -6.39 mm(3) (95% CI, -7.52 to -5.12), as compared with -4.42 mm(3) (95% CI, -5.98 to -3.26) (P=0.01). Both agents induced regression in the majority of patients: 63.2% with atorvastatin and 68.5% with rosuvastatin for PAV (P=0.07) and 64.7% and 71.3%, respectively, for TAV (P=0.02). Both agents had acceptable side-effect profiles, with a low incidence of laboratory abnormalities and cardiovascular events.

CONCLUSIONS: Maximal doses of rosuvastatin and atorvastatin resulted in significant regression of coronary atherosclerosis. Despite the lower level of LDL cholesterol and the higher level of HDL cholesterol achieved with rosuvastatin, a similar degree of regression of PAV was observed in the two treatment groups.

PMID: 22085316

Percutaneous Transvenous Melody Valve-in-Ring Procedure for Mitral Valve Replacement

OBJECTIVES: The purpose of this study was to demonstrate the feasibility of percutaneous transvenous mitral valve-in-ring (VIR) implantation using the Melody valve in an ovine model. The recurrence of mitral regurgitation following surgical mitral valve (MV) repair in both adult and pediatric patients remains a significant clinical problem. Mitral annuloplasty rings are commonly used in MV repair procedures and may serve as secure landing zones for percutaneous valves.

METHODS: Five sheep underwent surgical MV annuloplasty (24 mm, n = 2; 26 mm, n = 2; 28 mm, n = 1). Animals underwent cardiac catheterization with VIR implantation via a transfemoral venous, transatrial septal approach 1 week following surgery. Hemodynamic, angiographic, and echocardiographic data were recorded before and after VIR.

RESULTS: VIR was technically successful and required <1 h of procedure time in all animals. Fluoroscopy demonstrated securely positioned Melody valves within the annuloplasty ring in all animals. Angiography revealed no significant MV regurgitation in 4 and moderate central MV regurgitation in the animal with the 28-mm annuloplasty. All animals demonstrated vigorous left ventricular function, no outflow tract obstruction, and no aortic valve insufficiency.

CONCLUSIONS: This study demonstrated the feasibility of a purely percutaneous approach to MV replacement in patients with preexisting annuloplasty rings. This novel approach may be of particular benefit to patients with failed repair of ischemic mitral regurgitation and in pediatric patients with complex structural heart disease.

PMID: 22133846

Multimodality Imaging in Transcatheter Aortic Valve Implantation and Post-Procedural Aortic Regurgitation: Comparison Among Cardiovascular Magnetic Resonance, Cardiac Computed Tomography, and Echocardiography

OBJECTIVES: The purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment. The optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood.

METHODS: A total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE.

RESULTS: Of the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, –0.4 mm; 95% limits of agreement: –5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively).

CONCLUSIONS: In patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.

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Angiographic Disease Progression and Residual Risk of Cardiovascular Events While on Optimal Medical Therapy: Observations From the COURAGE Trial

OBJECTIVES: The extent to which recurrent events in patients with stable coronary artery disease is attributable to progression of an index lesion originally ≥50% diameter stenosis (DS) but not revascularized or originally <50% DS is unknown during optimal medical therapy (OMT).

METHODS: In the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial, 205 patients assigned to OMT plus percutaneous coronary intervention (PCI) and 284 patients assigned to OMT only had symptom-driven angiograms suitable for analysis.

RESULTS: Percentages of patients in the OMT+PCI and OMT-only cohorts with index lesions originally <50% DS were 30% and 32%, respectively; 20% and 68% had index lesions originally ≥50% DS. In both groups, index lesions originally <50% or ≥50% DS represented <4% and <25% of all such lesions, respectively. The only angiographic predictor of myocardial infarction or acute coronary syndrome was the number of lesions originally ≥50% DS that had not been revascularized (odds ratio, 1.15; confidence limits, 1.01–1.31; P<0.04).

CONCLUSIONS: Lesions originally <50% DS were index lesions in one third of patients referred for symptom-driven repeat angiography, but represented <4% of all such lesions. Nonrevascularized lesions originally ≥50% DS were more often index lesions in OMT-only patients, but still represented a minority (<25%) of all such lesions. These findings underscore the need for improved therapies to arrest plaque progression and reliable strategies for selecting stenoses warranting PCI.

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Diagnosis of Ischemia-Causing Coronary Stenoses by Noninvasive Fractional Flow Reserve Computed From Coronary Computed Tomographic Angiograms

OBJECTIVES: The aim of this study was to determine the diagnostic performance of a new method for quantifying fractional flow reserve (FFR) with computational fluid dynamics (CFD) applied to coronary computed tomography angiography (CCTA) data in patients with suspected or known coronary artery disease (CAD). Measurement of FFR during invasive coronary angiography is the gold standard for identifying coronary artery lesions that cause ischemia and improves clinical decision-making for revascularization. Computation of FFR from CCTA data (FFRCT) provides a noninvasive method for identifying ischemia-causing stenosis; however, the diagnostic performance of this new method is unknown.

METHODS: Computation of FFR from CCTA data was performed on 159 vessels in 103 patients undergoing CCTA, invasive coronary angiography, and FFR. Independent core laboratories determined FFRCT and CAD stenosis severity by CCTA. Ischemia was defined by an FFRCT and FFR 0.80, and anatomically obstructive CAD was defined as a CCTA with stenosis 50%. Diagnostic performance of FFRCT and CCTA stenosis was assessed with invasive FFR as the reference standard.

RESULTS: Fifty-six percent of patients had 1 vessel with FFR 0.80. On a per-vessel basis, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 84.3%, 87.9%, 82.2%, 73.9%, 92.2%, respectively, for FFRCT and were 58.5%, 91.4%, 39.6%, 46.5%, 88.9%, respectively, for CCTA stenosis. The area under the receiver-operator characteristics curve was 0.90 for FFRCT and 0.75 for CCTA (p = 0.001). The FFRCT and FFR were well correlated (r = 0.717, p < 0.001) with a slight underestimation by FFRCT (0.022 ± 0.116, p = 0.016).

CONCLUSIONS: Noninvasive FFR derived from CCTA is a novel method with high diagnostic performance for the detection and exclusion of coronary lesions that cause ischemia.

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Internal Pudendal Artery Stenoses and Erectile Dysfunction: Correlation With Angiographic Coronary Artery Disease

PMID: 20928837

Performance of Angiographic, Electrocardiographic and MRI Methods to Assess the Area at Risk in Acute Myocardial Infarction

OBJECTIVES: Validation of methods to assess the area at risk (AAR) in patients with ST elevation myocardial infarction is limited. A study was undertaken to test different AAR methods using established physiological concepts to provide a reference standard. Main outcome measuredIn 78 reperfused patients with first ST elevation myocardial infarction, AAR was measured by electrocardiographic (Aldrich), angiographic (Bypass Angioplasty Revascularization Investigation (BARI), APPROACH) and cardiovascular magnetic resonance methods (T2-weighted hyperintensity and delayed enhanced endocardial surface area (ESA)). The following established physiological concepts were used to evaluate the AAR

METHODS: (1) AAR size is always ≥ infarct size (IS); (2) in transmural infarcts AAR size=IS; (3) correlation between AAR size and IS increases as infarct transmurality increases; and (4) myocardial salvage ((AAR-IS)/AAR×100) is inversely related to infarct transmurality.

RESULTS: Overall, 65%, 87%, 76%, 87% and 97% of patients using the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods obeyed the concept that AAR size is ≥IS. In patients with transmural infarcts (n=22), Bland-Altman analysis showed poor agreement (wide 95% limits of agreement) between AAR size and IS for the BARI, Aldrich and APPROACH methods (95% CI -22.9 to 29.6, 95% CI -28.3 to 21.3 and 95% CI -16.9 to 20.0, respectively) and better agreement for T2-weighted hyperintensity and ESA (95% CI -6.9 to 16.6 and 95% CI -4.3 to 18.0, respectively). Increasing correlation between AAR size and IS with increasing infarct transmurality was observed for the APPROACH, T2-weighted hyperintensity and ESA methods, with ESA having the highest correlation (r=0.93, p

CONCLUSIONS: For measuring AAR, cardiovascular magnetic resonance methods are better than angiographic methods, which are better than electrocardiographic methods. Overall, ESA performed best for measuring AAR in vivo.

PMID: 21930725

Right Ventriculo-Arterial Coupling In Pulmonary Hypertension: A Magnetic Resonance Study

OBJECTIVES: To quantify right ventriculo-arterial coupling in pulmonary hypertension by combining standard right heart catheterisation (RHC) and cardiac magnetic resonance (CMR) and to estimate it non-invasively with CMR alone.

METHODS: This was a cross-sectional analysis in a retrospective cohort of consecutive patients from a tertiary care centre. There were 139 adults referred for pulmonary hypertension evaluation. Interventions: CMR and RHC within 2 days (n=151 test pairs). The main outcome measures right ventriculo-arterial coupling was quantified as the ratio of pulmonary artery (PA) effective elastance (Ea, index of arterial load) to right ventricular maximal end-systolic elastance (Emax, index of contractility). Right ventricular end-systolic volume (ESV) and stroke volume (SV) were obtained from CMR and adjusted to body surface area. RHC provided mean PA pressure (mPAP) as a surrogate of right ventricular end-systolic pressure, pulmonary capillary wedge pressure (PCWP) and pulmonary vascular resistance index (PVRI). Ea was calculated as (mPAP − PCWP)/SV and Emax as mPAP/ESV.

RESULTS: Ea increased linearly with advancing severity as defined by PVRI quartiles (0.19, 0.50, 0.93 and 1.63 mmHg/ml/m2, respectively; p

CONCLUSIONS: Right ventriculo-arterial coupling in pulmonary hypertension can be studied with standard RHC and CMR. Arterial load increases with disease severity whereas contractility cannot progress in parallel, leading to severe uncoupling.

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