Modification of a Transvalvular Microaxial Flow Pump for Instantaneous Determination of Native Cardiac Output and Volume.

BACKGROUND: The current Impella cardiopulmonary (CP) pump, used for mechanical circulatory support in patients with cardiogenic shock (CS), cannot assess native cardiac output (CO) and left ventricular (LV) volumes. These data are valuable in facilitating device management and weaning. Admittance technology allows for accurate assessment of cardiac chamber volumes. OBJECTIVES: This study tested the ability to engineer admittance electrodes onto an existing Impella CP pump to assess total and native CO as well as LV chamber volumes in an instantaneous manner. METHODS: Impella CP pumps were fitted with 4 admittance electrodes and were placed in the LVs of adult swine (n = 9) that were subjected to 3 different hemodynamic conditions, including Impella CP speed adjustments, administration of escalating doses of dobutamine and microsphere injections into the left main artery to result in cardiac injury. CO, according to admittance electrodes, was calculated from LV volumes and heart rate. In addition, CO was calculated in each instance via thermodilution, continuous CO measurement, the Fick principle, and aortic velocity-time integral by means of echocardiography. RESULTS: Modified Impella CP pumps were placed in swine LVs successfully. CO, as determined by admittance electrodes, was similar by trend to other methods of CO assessment. It was corrected for pump speed to calculate native CO, and calculated LV chamber volumes trended as expected in each experimental protocol. CONCLUSIONS: We report, for the first time, that an Impella CP pump can be fitted with admittance electrodes and used to determine total and native CO in various hemodynamic situations. CONDENSED ABSTRACT: Transvalvular mechanical circulatory support devices such as the Impella CP do not have the ability to provide real-time information on native cardiac output (CO) and left ventricular (LV) volumes. This information is critical in device management and in weaning in patients with cardiogenic shock. We demonstrate, for the first time, that Impella CP pumps coupled with admittance electrodes are able to determine native CO and LV chamber volumes in multiple hemodynamic situations such as Impella pump speed adjustments, escalating dobutamine administration and cardiac injury from microsphere injection.

Derivation and validation of Pd/Pa in the assessment of residual ischemia post-intervention: A prospective all-comer registry.

BACKGROUND: Measurement of post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) demonstrates residual ischemia in a large percentage of cases deemed angiographically successful which, in turn, has been associated with worse long-term outcomes. It has recently been shown that a resting pressure index, Pd/Pa, has prognostic value post stenting, however, its diagnostic value relative to FFR post-PCI has not been evaluated. METHODS: The diagnostic accuracy of Pd/Pa in identifying ischemia (FFR≤0.80) pre- and post-PCI was evaluated. Three patient subsets were analyzed. A reference pre-PCI cohort of 1,255 patients (1,560 vessels) was used to measure the accuracy of pre-PCI Pd/Pa vs. FFR. A derivation post-PCI group of 574 patient (664 vessels) was then used to calculate the diagnostic accuracy of post-PCI Pd/Pa vs. FFR. A final prospective validation cohort of 230 patients (255 vessels) was used to test and validate the diagnostic performance of post-PCI Pd/Pa. RESULTS: Median Pd/Pa and FFR were 0.90 (IQR 0.90-0.98) and 0.80 (IQR 0.71-0.88) in the reference pre-PCI model, 0.96 (IQR 0.93-1.00) and 0.87 (IQR 0.77-0.90) in the post-PCI derivation model, and 0.94 (IQR 0.89-0.97) and 0.84 (IQR 0.77-0.90) in the post-PCI validation model respectively. There was a strong linear correlation between Pd/Pa and FFR in all three models (p < 0.0001). Using ROC analysis, the optimal Pd/Pa cutoff value to predict a FFR ≤ 0.80 was ≤0.92 (AUC 0.87) in the pre-PCI model, ≤0.93 (AUC 0.85) in the post-PCI derivation model, and ≤ 0.90 (AUC 0.91) in the post-PCI validation model. Using a hybrid strategy of post-PCI Pd/Pa and post-PCI FFR when necessary (25% patients), overall diagnostic accuracy was improved to 95%. CONCLUSIONS: Pd/Pa has excellent diagnostic accuracy for identifying ischemia post-intervention. Using a hybrid strategy of post-PCI Pd/Pa first, and FFR afterwards, if required, adenosine administration can be avoided in over 75% of physiologic assessments post intervention.

Clinical and angiographic predictors of persistently ischemic fractional flow reserve after percutaneous revascularization.

AIMS: Despite optimal angiographic results after percutaneous coronary intervention (PCI), some lesions may continue to produce ischemia under maximal hyperemia. We evaluated the factors associated with persistently ischemic fractional flow reserve (FFR) after angiographically successful PCI. METHODS AND RESULTS: A total of 574 consecutive patients with 664 lesions undergoing PCI who had FFR pre- and post-PCI were analyzed. Percutaneous coronary intervention led to effective ischemia reduction from pre-FFR (0.65±0.14) to post-FFR (0.87±0.08; ∆FFR 0.22±0.16, P<.001). There were 63 (9.5%) lesions with a persistently ischemic FFR of ≤0.80 despite optimal angiographic PCI results. Multivariate analysis revealed the presence of diffuse disease (odds ratio [OR] 3.54, 95% CI 1.80-6.94, P<.01), left anterior descending artery PCI (OR 8.35, 95% CI 3.82-18.27, P<.01), use of intravenous adenosine for inducing hyperemia (OR 3.95, 95% CI 2.0-7.84, P<.01), and pre-PCI FFR (OR 0.03, 95% CI 0.004-0.23, P<.01) as independent predictors of persistently ischemic FFR (≤0.80) after PCI. The predictive accuracy of this model was robust, with an area under the curve of 0.85 (95% CI 0.82-0.88). CONCLUSION: Multiple factors are associated with persistently ischemic FFR after angiographically optimal PCI. It is recommended that in lesions with the above-identified factors, FFR should be remeasured after PCI, and if abnormal, further measures should be undertaken for functional optimization.

Role of fractional flow reserve in the evaluation and management of patients with acute coronary syndrome.

PURPOSE OF REVIEW: The aim of this review is to appraise the clinical and prognostic value and pitfalls of FFR across different spectra of ACS presentations and lesion subsets. RECENT FINDINGS: Preponderance of evidence on this subject is from observational nonrandomized studies with conflicting results and short-term outcomes. Multiple recent studies evaluating the role of FFR-based deferral in non-STE ACS from a potentially culprit lesion have demonstrated poor long-term prognosis as related to future risk of target vessel failure (myocardial infarction/revascularization). The prognostic power of nonischemic FFR seems favorable in clear nonculprit ACS lesions. SUMMARY: Fractional flow reserve evaluation can be helpful in clinical decision-making for certain subsets of ACS patients and lesions. Definite ACS-producing lesions should not be evaluated using FFR due to altered pathophysiology and distinct mechanisms underlying the disease process. In uncertain culprit lesions, FFR may be useful with complementary intracoronary imaging.

Perioperative Heparin Bridging in Atrial Fibrillation Patients Requiring Temporary Interruption of Anticoagulation: Evidence from Meta-analysis.

BACKGROUND: Patients with atrial fibrillation (AF) often require temporary interruption of warfarin for an elective operation or invasive procedure. However, the safety and efficacy of periprocedural bridging anticoagulation with unfractionated heparin (UH) or low-molecular-weight heparin (LMWH) are still unclear. We evaluated the safety of periprocedural heparin bridging in AF patients requiring temporary interruption of oral anticoagulation. METHODS: We searched the literature for trials that compared heparin bridging with no bridging in AF patients for whom warfarin was temporarily interrupted. The incidence of all-cause mortality, thromboembolism, and major and all bleeding was included, and meta-analysis was performed. RESULTS: A total of 13,808 patients with AF were included in 4 observational studies, 1 randomized trial, and 1 subgroup analysis of a randomized trial. The mean CHADS2 score for the no heparin bridging group was 2.49 and that for the heparin bridging group was 2.34. At 30 days and up to 3 months, when compared to the heparin bridging group, the no bridging group did not have any significant difference in mortality (odds ratio [OR], 1.29; 95% confidence interval [CI], .15-11.52; P = .82) or cerebrovascular accidents (OR, .93; 95% CI, .34-2.51; P = .88), but the no bridging group had significantly less major bleeding (OR, .41; 95% CI, .24-.68; P = .0006). CONCLUSION: Among AF patients with intermediate CHADS2 scores who are anticoagulated with warfarin and who required temporary interruption of warfarin for an elective surgery or procedure, periprocedural bridging with UH or LMWH was associated with a higher rate of major bleeding with no significant difference in mortality or CVA.

Role of multimodality imaging in transcatheter aortic valve replacement.

The treatment of aortic stenosis (AS) has reached an exciting stage with the introduction of transcatheter aortic valve replacement (TAVR). It is the treatment of choice in patients with severe AS who are considered very high risk for surgical valve replacement. Multimodality imaging (MMI) plays a crucial role in TAVR patient selection, intra-procedure guidance, and follow-up. With the ever-increasing scope for TAVR, a better understanding of MMI is essential to improve outcomes and prevent complications.

Echocardiography in patients with complications related to pacemakers and cardiac defibrillators.

The evolving indications and uses for implantable cardiac devices have led to a significant increase in the number of implanted devices each year. Implantation of endocardial leads for permanent pacemakers and cardiac defibrillators can cause many delayed complications. Complications may be mechanical and related to the interaction of the device leads with the valves and endomyocardium, e.g., perforation, infection, and thrombosis, or due to the electrical pacing of the myocardium and conduction abnormalities, e.g., left ventricular dyssynchrony. Tricuspid regurgitation, another delayed complication in these patients, may be secondary to both mechanical and pacing effects of the device leads. Echocardiography plays an important role in the diagnosis of these device-related complications. Both two-dimensional transthoracic echocardiography and transesophageal echocardiography provide useful diagnostic information. Real time three-dimensional echocardiography is a novel technique that can further enhance the detection of lead-related complications.

Percutaneous left atrial appendage closure for stroke prevention in hypertrophic cardiomyopathy patients with atrial fibrillation.

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) is an effective alternative strategy for stroke prevention in patients with atrial fibrillation (AF) at high risk for bleeding with anticoagulation (AC). Efficacy of this strategy in hypertrophic cardiomyopathy (HCM) remains uncertain. OBJECTIVE: The study aimed to compare risk of stroke in HCM-AF patients treated with LAAC with those treated with AC. METHODS: By use of the TriNetX Global Research Network, HCM-AF patients from 2015 to 2024 were assigned to categories of treatment with LAAC and treatment solely with AC and observed for 3 years for ischemic stroke, systemic embolism, and all-cause mortality. Propensity score matching was used to limit confounders. RESULTS: Of 14,867 HCM-AF patients identified, 364 (2.5%) were treated with LAAC vs 14,503 (97.5%) treated with AC. HCM LAAC patients were older (72 vs 67 years; P < .001) and had more comorbidities and more prior bleeding events, including higher rate of prior gastrointestinal bleeding (68% vs 18%; P < .001), compared with HCM patients treated solely with AC. After propensity score matching, there was no baseline difference between groups including prior bleeding events (P > .05). During follow-up, HCM patients treated with LAAC had higher rates of ischemic stroke (13% vs 8%; hazard ratio, 1.9; P = .006) and systemic embolism (14% vs 9%; hazard ratio, 1.8; P = .006) but no difference in mortality compared with matched HCM patients receiving AC. CONCLUSION: These real-world data do not support percutaneous LAAC in HCM-AF patients as the primary treatment strategy during long-term AC to reduce stroke risk. However, LAAC may remain a reasonable option for HCM-AF patients who are unable to tolerate AC because of prohibitive bleeding risk.

Direct Oral Anticoagulants for Rheumatic Heart Disease-Associated Atrial Fibrillation Post-Bioprosthetic Mitral Valve Replacement.

BACKGROUND: The efficacy of direct oral anticoagulants (DOACs) in preventing ischemic and thromboembolic events may be suboptimal in atrial fibrillation (AF) patients with rheumatic mitral stenosis. However, their safety and effectiveness after mitral valve replacement (MVR) using bioprosthetic valves is unclear. OBJECTIVES: This study sought to evaluate the safety and effectiveness of DOACs vs warfarin among patients with rheumatic heart disease (RHD)-associated AF after bioprosthetic MVR. METHODS: We performed an observational analysis identifying patients with RHD and AF who underwent bioprosthetic MVR. Primary effectiveness and safety outcomes were ischemic events and major bleeding, respectively. Secondary outcomes included all-cause mortality, cardiac thrombosis, myocardial infarction, and all-cause hospitalization. Propensity score matching was performed to account for the differences in baseline characteristics and comorbidities. RESULTS: A total of 3,950 patients were identified; 76% were on warfarin and 24% on DOAC post-MVR. The DOAC group had a higher burden of baseline comorbidities and prior cardiovascular procedures compared with the warfarin group. The propensity score matching balanced baseline characteristics in 1,832 patients (916 in each group), with a mean age of 69 years. At the 5-year follow-up, DOACs were associated with a lower incidence of major bleeding compared with warfarin (HR: 0.76; 95% CI: 0.62-0.94), with no significant difference in ischemic events, mortality, cardiac thrombosis, myocardial infarction, or hospitalization. CONCLUSIONS: Among patients with RHD-associated AF patients post-bioprosthetic MVR, DOACs are associated with lower major bleeding and comparable effectiveness, indicating a potential alternative to warfarin. Further randomized controlled trials are warranted to validate these findings in this population.

Incremental value of transthoracic real time three-dimensional echocardiography in assessment of a right ventricular mass.

A 52-year-old male with a right ventricular mass that filled the entire right ventricle and assumed its shape was evaluated by two-dimensional and real time three-dimensional (3D) echocardiography. Contrast enhanced 3D imaging and quantitative assessments of the size of the mass were performed. The clinical correlation, the imaging characteristics of the mass, and the pattern of vascularity were consistent with metastatic hepatocellular carcinoma. The case illustrates the incremental role of 3D echo in defining the size, shape, spatial relationship, attachments, consistency, and vascularity of the right ventricular mass.

Surgical and Transcatheter Mitral Valve Therapy: Medicare Utilization and Reimbursement.

BACKGROUND: We aimed to examine trends in the utilization and reimbursement of surgical and transcatheter mitral valve therapies and their changing relationship. METHODS: A query of administrative data on US Medicare beneficiaries undergoing mitral valve therapy was conducted from 2015 to 2020 using the Centers for Medicare and Medicaid Services Part B National Summary Data File. Inflation adjustment was to the 2020 Consumer Price Index. Trend analysis was quantified with growth rate and simple linear regression calculations. RESULTS: The annual number of all mitral valve procedures remained constant. Transcatheter mitral valve therapies increased by 313% with an increase of 1552 cases per year (P < .001), whereas surgical mitral valve therapies decreased by 31.4% with a decline of 1446 procedures per year (P = .004). As a proportion of all mitral valve therapies, surgical therapies decreased from 91.8% to 65.0%. Annual Medicare reimbursements for transcatheter and surgical mitral valve therapies mirrored the annual procedural trends. For transcatheter mitral valve therapies, per-case reimbursement decreased by 14.1% ($1283.18 to $1102.88), and for surgical mitral valve therapies, per-case reimbursement decreased by 3.8% ($1480.65 to $1424.57). CONCLUSIONS: Medicare utilization of mitral valve therapies has been stable in recent years, with growth of transcatheter volumes offset by a decrease in surgical volumes. This suggests that transcatheter therapy availability has not expanded the pool of patients with access to therapy. Nonetheless, case reimbursements decreased for both modalities.

Innovative Approach to Manage Transcatheter Aortic Valve Embolization.

We describe the case of a patient with an ascending aortic aneurysm who underwent valve-in-valve transcatheter aortic valve implantation, which was complicated by valve embolization. After a multidisciplinary discussion and an innovative approach, the free-floating embolized valve was anchored securely in the aortic arch with an uncovered aortic endovascular stent. (Level of Difficulty: Intermediate.).

Evaluating Equivocal Left Main Stenosis with Fractional Flow Reserve - Not all Daughter Vessels are Created Equally.

Fractional flow reserve (FFR) evaluation of intermediate left main coronary artery (LMCA) stenosis has been validated in clinical decision-making. However, the size of the daughter vessel, in which the FFR transducer is placed and the amount of myocardium it subtends, has received less attention. We present a case that demonstrates the importance of transducer location, size of the daughter vessel and the amount of subtended myocardium in evaluation of LMCA stenosis, pointing out potential pitfalls.

Association Between Diastolic Dysfunction and Health Status Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

OBJECTIVES: The aim of this study was to assess the association of baseline left ventricular diastolic dysfunction (LVDD) with health status outcomes of patients undergoing transcatheter aortic valve replacement (TAVR). BACKGROUND: Although LVDD in patients with aortic stenosis is associated with higher mortality after TAVR, it is unknown if it is also associated with health status recovery. METHODS: In a cohort of 304 patients with interpretable echocardiograms, undergoing TAVR, LVDD was categorized at baseline as absent (grade 0), mild (grade 1), moderate (grade 2), or severe (grade 3). Disease-specific health status was assessed using the 12-item Kansas City Cardiomyopathy Questionnaire overall summary score (KCCQ-OS) at baseline and at 1-month and 12-month follow-up. Association of baseline LVDD with health status at baseline and follow-up after TAVR was assessed using a linear trend test, and association with health status recovery (change in KCCQ-OS) was examined using a linear mixed model adjusting for baseline KCCQ-OS. RESULTS: Twenty-four (7.9%), 54 (17.8%), 186 (61.2%), and 40 (13.2%) patients had LVDD grades of 0, 1, 2, and 3, respectively. Baseline KCCQ-OS was 61.3 ± 22.7, 51.0 ± 26.1, 44.7 ± 25.7, and 44.4 ± 21.9 (p = 0.004) in patients with LVDD grades of 0, 1,2 and 3. At 1 and 12 months after TAVR, LVDD was not associated with KCCQ-OS. Recovery in KCCQ-OS after TAVR was substantial and similar in patients across all severities of LVDD. CONCLUSIONS: Although LVDD is associated with health status prior to TAVR, patients across all severities of LVDD have similar recovery in health status after TAVR.

Outcomes of Fractional Flow Reserve-Based Deferral in Saphenous Vein Graft Narrowing.

Fractional flow reserve (FFR) has been shown to improve clinical decision-making for revascularization in intermediate coronary stenosis in native coronary arteries of patients with stable coronary disease. However, its use for saphenous vein graft (SVG) lesions has not been well validated. We sought to determine the prognostic value of deferring intervention in lesions with FFR >0.8 in SVG lesions. Clinical, angiographic, and hemodynamic variables and long-term outcomes were recorded in consecutive patients in whom percutaneous coronary intervention was deferred based on an FFR >0.8 for intermediate native coronary artery or SVG stenosis. Thirty-three patients underwent FFR of SVG lesions and were compared with 532 patients who underwent native vessel FFR during the same period. There were no differences in age (66.6 [interquartile range, IQR 63 to 76] vs 65 years [IQR 61 to 70]; p = 0.12), diabetes (41% vs 50%; p = 0.35), or hypertension (94% vs 97%; p = 0.71). During a median follow-up of 3.2 years (IQR 1.7 to 4.6 years) major adverse cardiac event was significantly higher in SVG group (36% vs 21%; log rank p = 0.01). Similarly, the rate of target vessel failure was significantly higher in the SVG group (27% vs 14%; p = 0.01). Deferred SVG lesions had the worst survival free of target vessel failure compared with deferred native lesions in both patients with and without previous CABG. An SVG lesion was an independent predictor of major adverse cardiac events on Cox proportional hazards analysis (hazard ratio 2.26; confidence interval 1.19, 4.28; p = 0.01). In conclusion, nonischemic FFR carries a significantly worse prognosis in SVG compared with non-SVG lesions. Caution is warranted in utilizing FFR for clinical decision-making in SVG lesions.

Long Term Risk of Recurrent Atrial Fibrillation and Ischemic Stroke after Post-Operative Atrial Fibrillation Complicating Cardiac and Non-Cardiac Surgeries.

BACKGROUND: New onset post-operative atrial fibrillation (POAF) can complicate both non-cardiac(NCS) and cardiac(CS) surgeries. Long term differences in recurrence of atrial fibrillation (AF) and incidence of ischemic stroke/transient ischemic attack(CVA)between these types of POAFare lacking. OBJECTIVE: To compare thelong term recurrence rate of AF and incidence of CVAin patients withnew onset POAF after CS and NCS. METHODS: All patients who developed POAF between May 2010 and April 2014 were included in this single-center, retrospective study Exclusion criteria included a prior history of atrial tachyarrhythmias and pre-operative use of anti-arrhythmic drugs. Recurrence of atrial fibrillation and CVA was identified by review of medical records, electrocardiogram and Holter monitor. RESULTS: patients identified by the ICD9 code=523, 112 patients (61 cardiac; 51 non-cardiac) met inclusion criteria. Mean follow up was 943 days (range 32-2052 days).AF recurrence rate within 30 days after hospital discharge was higher in CS compared with NCS(10% vs 0%, p =0.03). Kaplan Meier analysis showed a trend towards higher recurrence in NCS compared with CS(HR 2.8; 95% CI 0.78-10.6, log rank p =0.03).In long term follow-up, CVA was numerically more common in patients with POAF after CS compared withNCS(10% vs 2%) though this difference was non-significant(HR 3.1; 95% CI 0.72-13.3; log rank p =0.26). CONCLUSION: The risk of recurrent AF and ischemic stroke is not different between POAF after CS or NCS. The overall high rate of AF recurrence and risk of ischemic stroke mandate careful long term follow-up.

Correlation between Echocardiographic Pulmonary Artery Pressure Estimates and Right Heart Catheterization Measurement in Liver Transplant Candidates.

BACKGROUND: Patients undergoing liver transplant have worse outcomes in the presence of pulmonary hypertension. Correlation between echocardiography and catheterization derived pressures in this population is not well studied. Our study's aim is to show the relationship between pulmonary artery systolic pressure derived from transthoracic echo (ePASP) with pulmonary artery systolic pressure measured during right heart catheterization (cPASP). METHODS: Single center retrospective study, patients being evaluated for liver transplant (n = 31) who had an interpretable Doppler signal for ePASP and had right heart catheterization (RHC) measurements within 3 months constituted the study group. Control group (n = 49) consisted of patients who did not have liver disease. RESULTS: There was modest correlation between ePASP and cPASP (R = 0.58, p < 0.001) in LT candidates (n = 31) compared with the control group (R = 0.74, p < 0.001, n = 49). The 95% limits of agreement by Bland-Altman analysis ranged from +33.6 mmHg to -21.7 mmHg. Using receiver operating characteristic analysis, ePASP cut-off > 47 mmHg was 59% sensitive and 78% specific to diagnose pulmonary artery (PA) hypertension (mean PA pressure > 25 mmHg) in the LT candidates, while a similar cutoff performed well in the control group (cutoff > 43 mmHg, n = 47, 91% sensitive, 100% specific). CONCLUSIONS: Compared with other disease states, ePASP correlates modestly with cPASP in patients with advanced liver disease. A higher ePASP cutoff should be used to screen for pulmonary hypertension. A multi-center prospective study with simultaneous transthoracic echocardiography and RHC measurements is required to determine the best cut-off in this population.

Comparison of the prognostic value of non-ischaemic fractional flow reserve using intracoronary versus intravenous adenosine.

AIMS: Intracoronary adenosine (ICA) yields similar fractional flow reserve (FFR) results to the "gold standard" of intravenous adenosine (IVA). Whether they have similar prognostic significance is unknown. We therefore sought to study the prognostic value of the route of adenosine administration for the measurement of FFR in deferred coronary lesions in a large, real-world cohort. METHODS AND RESULTS: Five hundred and seventy-six patients with 787 lesions in whom PCI was deferred based on FFR >0.75 were studied. The primary outcome was the first major adverse cardiovascular event (MACE; defined as death, myocardial infarction [MI], or target vessel revascularisation [TVR]), and the secondary outcome was a composite of MI and target vessel failure (TVF). FFR was measured with ICA in 426 lesions and IVA in 361 lesions. Median follow-up duration was 3.2 years (interquartile range: 1.7- 4.6). Propensity-matched cohorts of ICA and IVA were well matched for baseline clinical, angiographic and haemodynamic characteristics. In the propensity-matched cohort, MACE occurred in 23.5% of the ICA group and in 22.3% of the IVA group (p=0.29). On multivariate analysis, acute coronary syndrome, FFR and prior MI/revascularisation were independent predictors of MACE and MI/TVF. The route of adenosine administration was not predictive of MACE or MI/TVF. CONCLUSIONS: ICA and IVA yield similar FFR values and show comparable long-term prognostic utility in a deferred population. These findings provide confirmation that non-ischaemic FFR using a simpler ICA protocol provides prognostic data similar to the gold standard IVA.