Continuous thermodilution and microvascular resistance reserve during the index procedure in acute coronary syndrome without obstructive coronary artery disease: A pilot study.

BACKGROUND: In 5%-25% of non-ST-elevation acute coronary syndrome (NSTE-ACS) patients, coronary angiography reveals no obstructive coronary arteries (MINOCA). Coronary microvascular disease (CMD) is a potential causal pathophysiological mechanism in these patients and can be diagnosed by continuous thermodilution assessment. Recently, the microvascular resistance reserve (MRR) has been introduced as a novel index to assess the vasodilatory capacity of the microcirculation. However, continuous thermodilution and MRR have never been investigated in the acute setting in MINOCA patients and invasive assessment of the microcirculation in these patients are currently lacking. AIMS: The objectives of the study were to investigate the incidence of CMD (MRR ≤ 2.7) in patients with MINOCA and to evaluate the feasibility and safety of continuous thermodilution-based assessment during index coronary angiography in the acute setting. METHODS: This study was a prospective, observational, pilot study investigating coronary physiology in the acute setting in MINOCA patients. Patients admitted with a diagnosis of NSTE-ACS were eligible for inclusion. RESULTS: In total, 19 MINOCA patients were included in this analysis; the mean age was 70 ± 9 years, and 79% were females. CMD was present in 6 patients (32%). Qrest was significantly higher in the MRR ≤ 2.7 group compared to the MRR > 2.7 group (0.076 [0.057-0.100] vs. 0.049 [0.044-0.071] L/min, p = 0.03). Rµ,rest was significantly lower in the MRR ≤ 2.7 group compared to the MRR > 2.7 group (1083 [710-1510] vs. 1563 [1298-1970] WU, p = 0.04). No periprocedural complications or hemodynamic instability have occurred during continuous thermodilution assessment during the index coronary angiography. CONCLUSION: In patients admitted for MINOCA undergoing immediate coronary angiography, continuous thermodilution assessment and MRR are feasible and safe in the acute setting, and evidence of functional CMD could be observed in one-third of the MINOCA patients.

Influence of Pathophysiological Patterns of Coronary Artery Disease on Immediate Percutaneous Coronary Intervention Outcomes.

BACKGROUND: Diffuse coronary artery disease (CAD) impacts the safety and efficacy of percutaneous coronary intervention (PCI). Pathophysiological CAD patterns can be quantified using fractional flow reserve (FFR) pullbacks incorporating the pullback pressure gradient (PPG) calculation. This study aimed to establish the capacity of PPG to predict optimal revascularisation and procedural outcomes. METHODS: This prospective, investigator-initiated, single-arm, multicentre study enrolled patients with at least one epicardial lesion with an FFR ≤ 0.80 scheduled for PCI. Manual FFR pullbacks were employed to calculate PPG. The primary outcome of optimal revascularisation was defined as a post-PCI FFR ≥ 0.88. RESULTS: 993 patients with 1044 vessels were included. The mean FFR was 0.68 ± 0.12, PPG 0.62 ± 0.17, and post-PCI FFR 0.87 ± 0.07. PPG was significantly correlated with the change in FFR after PCI (r=0.65, 95% CI 0.61-0.69, p<0.001) and demonstrated excellent predicted capacity for optimal revascularisation (AUC 0.82, 95% CI 0.79-0.84, p<0.001). Conversely, FFR alone did not predict revascularisation outcomes (AUC 0.54, 95% CI 0.50-0.57). PPG influenced treatment decisions in 14% of patients, redirecting them from PCI to alternative treatment modalities. Periprocedural myocardial infarction occurred more frequently in patients with low PPG (<0.62) compared to those with focal disease (OR 1.71, 95% CI: 1.00-2.97). CONCLUSIONS: Pathophysiological CAD patterns distinctly affect the safety and effectiveness of PCI. The PPG showed an excellent predictive capacity for optimal revascularisation and demonstrated added value compared to a FFR measurement.

Prognostic Value of Microvascular Resistance Reserve After Percutaneous Coronary Intervention in Patients With Myocardial Infarction.

BACKGROUND: The microvascular resistance reserve (MRR) has recently been introduced as a novel index to assess the vasodilatory capacity of the microcirculation, independent of epicardial disease. The prognostic value of MRR in ST-segment elevation myocardial infarction (STEMI) is unknown. OBJECTIVES: The aim of this analysis was to investigate the prognostic value of MRR in patients with STEMI and to compare MRR with cardiovascular magnetic resonance imaging parameters. METHODS: From a pooled analysis of individual patient data from 6 cohorts that measured the index of microcirculatory resistance (IMR) directly after primary percutaneous coronary intervention in patients with STEMI (n = 1,265), a subgroup analysis was performed in patients in whom both MRR and IMR were available. The primary endpoint was the composite of all-cause mortality or hospitalization for heart failure. RESULTS: Both MRR and IMR could be calculated in 446 patients. The optimal cutoff of MRR to predict the primary endpoint in this STEMI population was 1.25. During a median follow-up of 3.1 years (Q1-Q3: 1.5-6.1 years), the composite of all-cause mortality or hospitalization for heart failure occurred in 27.3% and 5.9% of patients (HR: 4.16; 95% CI: 2.31-7.50; P < 0.001) in the low MRR (≤1.25) and high MRR (>1.25) groups, respectively. Both IMR and MRR were independent predictors of the composite of all-cause mortality or hospitalization for heart failure. CONCLUSIONS: MRR measured directly after primary percutaneous coronary intervention was an independent predictor of the composite of all-cause mortality or hospitalization for heart failure during long-term follow-up.

Fluid-filled versus sensor-tipped pressure guidewires for FFR and Pd/Pa measurement; PW-COMPARE study.

BACKGROUND: Fluid-filled pressure guidewires are unaffected by the previously inevitable hydrostatic pressure gradient (HPG). This study aimed to compare simultaneous pressure measurements with fluid-filled and sensor-tipped pressure guidewires. METHODS: Fifty patients underwent fractional flow reserve (FFR) and Pd/Pa measurement with a fluid-filled and a sensor-tipped pressure guidewire simultaneously. To assess maneuverability, patients were randomized with respect to which pressure guidewire was used to cross the lesion first. Lateral fluoroscopy was used to estimate height difference between catheter tip and distal wire position (and thus HPG). Agreement between pressure measurements was studied. RESULTS: Measurements were performed in LM (4% (n = 2)), LAD (44% (n = 22)), LCX (26% (n = 13)), and RCA (26% (n = 13)). Simultaneous pressure measurements showed excellent agreement (mean FFR difference - 0.01 ± 0.03 (r = 0.959, p < 0.001), mean Pd/Pa difference - 0.01 ± 0.04 (r = 0.929, p < 0.001)). FFR was ≤0.80 in 42.6% (n = 20) with fluid-filled FFR measurements versus 46.8% (n = 22) by sensor-tipped FFR measurements. Mean height difference was 15 ± 34 mm, and strongly dependent on the coronary artery (LAD 45 ± 10 mm, LCX -23 ± 16 mm, RCA -13 ± 17 mm). There was a strong correlation between height difference and difference in pressure ratios between sensor-tipped and fluid-filled pressure guidewires (FFR r = -0.850, p < 0.001; Pd/Par = -0.641, p < 0.001). Largest FFR differences were present in the LAD (-0.04 ± 0.02). After HPG correction, mean difference between HPG-corrected sensor-tipped FFR and fluid-filled FFR was 0.00 ± 0.02, mean Pd/Pa difference was 0.01 ± 0.03. CONCLUSIONS: This study shows excellent overall correlation between FFR and Pd/Pa measurements with both pressure guidewires. Differences measured with fluid-filled and sensor-tipped pressure guidewires are vessel-specific and attributable to hydrostatic pressure gradients (NCT04802681).

The Index of Microcirculatory Resistance After Primary PCI: A Pooled Analysis of Individual Patient Data.

BACKGROUND: Despite treatment with primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI), the risk of heart failure and late death remains high. Microvascular dysfunction, as assessed by the index of microcirculatory resistance (IMR), after primary PCI for STEMI has been associated with worse outcomes. It is unclear whether IMR after primary PCI predicts cardiac death. OBJECTIVES: The aims of this analysis were: 1) to determine if IMR is an independent predictor of cardiac death; 2) to assess the optimal cutoff value of IMR after STEMI; and 3) to compare IMR with several cardiac magnetic resonance parameters, including infarct size. METHODS: In a collaborative, pooled analysis of individual patient data from 6 cohorts that measured IMR directly after primary PCI, cardiac mortality up to 5 years was estimated using Kaplan-Meier analyses. The primary endpoint was cardiac death using the predefined IMR cutoff value of 40. RESULTS: In total, 1,265 patients were included in this study with a median follow-up of 2.8 years (IQR: 1.2-5.0 years). Cardiac death at 5 years occurred in 2.2% and 4.9% of patients (HR: 2.81; 95% CI: 1.34-5.88; P = 0.006) in the IMR ≤40 and IMR >40 groups, respectively. The composite of cardiac death or hospitalization for heart failure occurred in 4.9% and 8.9% (HR: 1.98; 95% CI: 1.20-3.29; P = 0.008) in the IMR ≤40 and IMR >40 groups, respectively. IMR was an independent predictor of cardiac death, whereas coronary flow reserve was not. The optimal cutoff value of IMR for the prediction of cardiac death in this cohort was 70 (HR: 4.73; 95% CI: 2.27-9.83; P < 0.001). Infarct size was 17.6% ± 13.3% and 23.9% ± 14.6% of the left ventricular mass in the IMR ≤40 and IMR >40 groups, respectively (P < 0.001). Microvascular obstruction and intramyocardial hemorrhage occurred more frequently in the IMR >40 group than in the IMR ≤40 group. CONCLUSIONS: In this large, pooled analysis of individual patient data, IMR measured directly after primary PCI in STEMI was an independent predictor of cardiac death. IMR may be used as a tool to identify patients at the time of primary PCI who are at highest risk for late cardiac mortality and who might benefit most from additional cardioprotective therapies and monitoring.

Bifurcation PCI with a hybrid strategy with drug- eluting balloons versus a stepwise provisional two- stent strategy: Rationale and design of the hybrid DEB study.

The optimal treatment strategy for coronary bifurcation lesions by percutaneous coronary intervention (PCI) is complex and remains a subject of debate. Current guidelines advise a stepwise provisional approach with optional two-stent strategy. However, a two-stent strategy, both upfront and stepwise provisional, is technically demanding. Therefore, there is increasing interest in the use of drug-eluting balloons (DEB) in bifurcation lesions, mainly after a provisional approach with unsatisfactory result of the side branch. Some small pilot studies already showed that the use of DEB in bifurcation lesions is safe and feasible. However, a randomized comparison of this hybrid DEB strategy with a two-stent strategy is currently lacking. TRIAL DESIGN: The Hybrid DEB study is a prospective, multicenter, randomized controlled trial investigating noninferiority of a hybrid DEB approach, using a combination of a drug-eluting stent (DES) in the main vessel and DEB in the side branch, compared to stepwise provisional two-stent strategy in patients with true bifurcation lesions. A total of 500 patients with de novo true coronary bifurcation lesions, treated with a stepwise provisional approach and an unsatisfactory result of the side branch after main vessel stenting (≥ 70% stenosis and/or < thrombolysis in myocardial infarction III flow), will be randomized in a 1:1 ratio to receive either treatment with a DEB or with a DES in the side branch. The primary endpoint is a composite endpoint of the occurrence of all-cause death, periprocedural or spontaneous myocardial infarction and/or target vessel revascularization at the anticipated median 2-year follow-up. CONCLUSION: The Hybrid DEB study will compare in a multicenter, randomized fashion a hybrid DEB approach with a stepwise provisional two-stent strategy in patients with true bifurcation lesions. TRIAL REGISTRATION: ClinicalTrials.gov no. NCT05731687.

Outcomes Based on Angiographic vs Functional Significance of Complex 3-Vessel Coronary Disease: FAME 3 Trial.

BACKGROUND: The functional SYNTAX score (FSS), which incorporates functional information as assessed by fractional flow reserve (FFR), is a better predictor of outcome after percutaneous coronary intervention (PCI) in patients with less complex coronary artery disease (CAD). OBJECTIVES: This study sought to test the prognostic value of the FSS in patients with complex CAD eligible for coronary artery bypass grafting (CABG). METHODS: The FAME 3 (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation 3) trial compared FFR-guided PCI with CABG in patients with angiographic 3-vessel CAD. In this prespecified substudy, the angiographic core laboratory calculated the SYNTAX score (SS) and then the FSS by eliminating lesions that were not significant based on FFR. Outcomes in the PCI patients based on the FSS and the SS were compared to each other and to the patients treated with CABG. RESULTS: The FSS reclassified more than one-quarter of patients from an SS >22 to an FSS ≤22. In the 50% of PCI patients who had an FSS ≤22, the primary endpoint occurred at a similar rate to patients treated with CABG (P = 0.77). The primary endpoint in patients without functionally significant 3-vessel CAD was similar to the CABG group (P = 0.97). The rate of myocardial infarction and revascularization among all deferred lesions was 0.5% and 3.2%, respectively. CONCLUSIONS: By measuring the FSS, one can identify 50% of patients who have a similar outcome at 1 year with PCI compared with CABG. Lesions deferred from PCI based on FFR have a low event rate.

Fractional Flow Reserve-Guided PCI or Coronary Bypass Surgery for 3-Vessel Coronary Artery Disease: 3-Year Follow-Up of the FAME 3 Trial.

BACKGROUND: Previous studies comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel coronary disease not involving the left main have shown significantly lower rates of death, myocardial infarction (MI), or stroke after CABG. These studies did not routinely use current-generation drug-eluting stents or fractional flow reserve (FFR) to guide PCI. METHODS: FAME 3 (Fractional Flow Reserve versus Angiography for Multivessel Evaluation) is an investigator-initiated, multicenter, international, randomized trial involving patients with 3-vessel coronary artery disease (not involving the left main coronary artery) in 48 centers worldwide. Patients were randomly assigned to receive FFR-guided PCI using zotarolimus drug-eluting stents or CABG. The prespecified key secondary end point of the trial reported here is the 3-year incidence of the composite of death, MI, or stroke. RESULTS: A total of 1500 patients were randomized to FFR-guided PCI or CABG. Follow-up was achieved in >96% of patients in both groups. There was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI compared with CABG (12.0% versus 9.2%; hazard ratio [HR], 1.3 [95% CI, 0.98-1.83]; P=0.07). The rates of death (4.1% versus 3.9%; HR, 1.0 [95% CI, 0.6-1.7]; P=0.88) and stroke (1.6% versus 2.0%; HR, 0.8 [95% CI, 0.4-1.7]; P=0.56) were not different. MI occurred more frequently after PCI (7.0% versus 4.2%; HR, 1.7 [95% CI, 1.1-2.7]; P=0.02). CONCLUSIONS: At 3-year follow-up, there was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI with current-generation drug-eluting stents compared with CABG. There was a higher incidence of MI after PCI compared with CABG, with no difference in death or stroke. These results provide contemporary data to allow improved shared decision-making between physicians and patients with 3-vessel coronary artery disease. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Rationale and design of the pullback pressure gradient (PPG) global registry.

INTRODUCTION: Diffuse disease has been identified as one of the main reasons leading to low post-PCI fractional flow reserve (FFR) and residual angina after PCI. Coronary pressure pullbacks allow for the evaluation of hemodynamic coronary artery disease (CAD) patterns. The pullback pressure gradient (PPG) is a novel metric that quantifies the distribution and magnitude of pressure losses along the coronary artery in a focal-to-diffuse continuum. AIM: The primary objective is to determine the predictive capacity of the PPG for post-PCI FFR. METHODS: This prospective, large-scale, controlled, investigator-initiated, multicenter study is enrolling patients with at least 1 lesion in a major epicardial vessel with a distal FFR ≤ 0.80 intended to be treated by PCI. The study will include 982 subjects. A standardized physiological assessment will be performed pre-PCI, including the online calculation of PPG from FFR pullbacks performed manually. PPG quantifies the CAD pattern by combining several parameters from the FFR pullback curve. Post-PCI physiology will be recorded using a standardized protocol with FFR pullbacks. We hypothesize that PPG will predict optimal PCI results (post-PCI FFR ≥ 0.88) with an area under the ROC curve (AUC) ≥ 0.80. Secondary objectives include patient-reported and clinical outcomes in patients with focal vs. diffuse CAD defined by the PPG. Clinical follow-up will be collected for up to 36 months, and an independent clinical event committee will adjudicate events. RESULTS: Recruitment is ongoing and is expected to be completed in the second half of 2023. CONCLUSION: This international, large-scale, prospective study with pre-specified powered hypotheses will determine the ability of the preprocedural PPG index to predict optimal revascularization assessed by post-PCI FFR. In addition, it will evaluate the impact of PPG on treatment decisions and the predictive performance of PPG for angina relief and clinical outcomes.

Transcatheter repair of massive primary mitral regurgitation: beyond the reach of the guidelines.

A 58-year-old male with prior history of mechanical aortic valve replacement (AVR) in 2009 for severe symptomatic aortic regurgitation in a bicuspid aortic valve, and since 2013 a new-onset severe asymptomatic primary mitral regurgitation (MR) due to prolapse of the anterior mitral valve leaflet (AMVL) presented himself with acute heart failure. Based on current guidelines recommendations, this patient was not eligible for transcutaneous mitral valve edge-to-edge repair (TEER), as well he was found as too high risk for conventional mitral valve repair. However, as a last resort TEER was undertaken with an unconventional strategy, which resulted in resolution of the MR and improvement of clinical, biochemical findings.

Prognostic Value of Measuring Fractional Flow Reserve After Percutaneous Coronary Intervention in Patients With Complex Coronary Artery Disease: Insights From the FAME 3 Trial.

BACKGROUND: We evaluate the prognostic value of measuring fractional flow reserve (FFR) after percutaneous coronary intervention (post-PCI FFR) and intravascular imaging in patients undergoing PCI for 3-vessel coronary artery disease in the FAME 3 trial (Fractional Flow Reserve versus Angiography for Multivessel Evaluation). METHODS: The FAME 3 trial is a multicenter, international, randomized study comparing FFR-guided PCI with coronary artery bypass grafting in patients with multivessel coronary artery disease. PCI was not noninferior with respect to the primary end point of death, myocardial infarction, stroke, or repeat revascularization at 1 year. Post-PCI FFR data were acquired on a patient and vessel-related basis. Intravascular imaging guidance was tracked. The primary end point is a comparison of target vessel failure (TVF) defined as a composite of cardiac death, target vessel myocardial infarction, and target vessel revascularization at 1 year based on post-PCI FFR values. Cox regression with robust SEs was used for analysis. RESULTS: Of the 757 patients randomized to PCI, 461 (61%) had post-PCI FFR measurement and 11.1% had intravascular imaging performed. The median post-PCI FFR was 0.89 [IQR' 0.85-0.94]. On a vessel-level, post-PCI FFR was found to be a significant predictor of TVF univariately (hazard ratio=0.67 [95% CI' 0.48-0.93] for 0.1 unit increase, P=0.0165). On a patient-level, the single lowest post-PCI FFR value was also found to be a significant predictor of TVF univariately (hazard ratio=0.65 [95% CI' 0.48-0.89] for 0.1 unit increase, P=0.0074). Post-PCI FFR was an independent predictor of TVF in multivariable analysis adjusted for key clinical parameters. Outcomes were similar between patients who had intravascular imaging guidance and those who did not. CONCLUSIONS: Post-PCI FFR measurement was a significant predictor of TVF on a vessel and patient level and an independent predictor of outcomes in a population with complex 3-vessel coronary artery disease eligible for coronary artery bypass grafting. The limited use of intravascular imaging did not affect outcomes. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Quality of Life After Fractional Flow Reserve-Guided PCI Compared With Coronary Bypass Surgery.

BACKGROUND: Previous studies have shown that quality of life improves after coronary revascularization more so after coronary artery bypass grafting (CABG) than after percutaneous coronary intervention (PCI). This study aimed to evaluate the effect of fractional flow reserve guidance and current generation, zotarolimus drug-eluting stents on quality of life after PCI compared with CABG. METHODS: The FAME 3 trial (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) is a multicenter, international trial including 1500 patients with 3-vessel coronary artery disease who were randomly assigned to either CABG or fractional flow reserve-guided PCI. Quality of life was measured using the European Quality of Life-5 Dimensions (EQ-5D) questionnaire at baseline and 1 and 12 months. The Canadian Cardiovascular Class angina grade and working status were assessed at the same time points and at 6 months. The primary objective was to compare EQ-5D summary index at 12 months. Secondary end points included angina grade and work status. RESULTS: The EQ-5D summary index at 12 months did not differ between the PCI and CABG groups (difference, 0.001 [95% CI, -0.016 to 0.017]; P=0.946). The trajectory of EQ-5D during the 12 months differed (P<0.001) between PCI and CABG: at 1 month, EQ-5D was 0.063 (95% CI, 0.047 to 0.079) higher in the PCI group. A similar trajectory was found for the EQ (EuroQol) visual analogue scale. The proportion of patients with Canadian Cardiovascular Class 2 or greater angina at 12 months was 6.2% versus 3.1% (odds ratio, 2.5 [95% CI, 0.96-6.8]), respectively, in the PCI group compared with the CABG group. A greater percentage of younger patients (<65 years old) were working at 12 months in the PCI group compared with the CABG group (68% versus 57%; odds ratio, 3.9 [95% CI, 1.7-8.8]). CONCLUSIONS: In the FAME 3 trial, quality of life after fractional flow reserve-guided PCI with current generation drug-eluting stents compared with CABG was similar at 1 year. The rate of significant angina was low in both groups and not significantly different. The trajectory of improvement in quality of life was significantly better after PCI, as was working status in those <65 years old. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Hypothermia for Cardioprotection in Patients with St-Elevation Myocardial Infarction: Do Not Give It the Cold Shoulder Yet!

The timely revascularization of an occluded coronary artery is the cornerstone of treatment in patients with ST-elevation myocardial infarction (STEMI). As essential as this treatment is, it can also cause additional damage to cardiomyocytes that were still viable before reperfusion, increasing infarct size. This has been termed "myocardial reperfusion injury". To date, there is still no effective treatment for myocardial reperfusion injury in patients with STEMI. While numerous attempts have been made to overcome this hurdle with various experimental therapies, the common denominator of these therapies is that, although they often work in the preclinical setting, they fail to demonstrate the same results in human trials. Hypothermia is an example of such a therapy. Although promising results were derived from experimental studies, multiple randomized controlled trials failed to do the same. This review includes a discussion of hypothermia as a potential treatment for myocardial reperfusion injury, including lessons learned from previous (negative) trials, advanced techniques and materials in current hypothermic treatment, and the possible future of hypothermia for cardioprotection in patients with STEMI.