Percutaneous coronary intervention of native coronary artery versus saphenous vein graft in patients with prior coronary artery bypass graft surgery: Rationale and design of the multicenter, randomized PROCTOR trial.

BACKGROUND: Patients with prior coronary artery bypass grafting (CABG) frequently require repeat percutaneous revascularization due to advanced age, progressive coronary artery disease and bypass graft failure. Percutaneous coronary intervention (PCI) of either the bypass graft or the native coronary artery may be performed. Randomized trials comparing native vessel PCI with bypass graft PCI are lacking and long-term outcomes have not been reported. METHODS: PROCTOR (NCT03805048) is a prospective, multicenter, randomized controlled trial, that will include 584 patients presenting with saphenous vein graft (SVG) failure and a clinical indication for revascularization, as determined by the local Heart Team. The trial is designed to compare the clinical and angiographic outcomes in patients randomly allocated in a 1:1 fashion to either a strategy of native vessel PCI or SVG PCI. The primary study endpoint is a 3-year composite of major adverse cardiac events (MACE: all-cause mortality, non-fatal target coronary territory myocardial infarction [MI], or clinically driven target coronary territory revascularization). At 3-years, after evaluation of the primary endpoint, follow-up invasive coronary angiography will be performed. Secondary endpoints comprise individual components of MACE at 1, 3 and 5 years follow-up, PCI-related MI, MI >48 hours after index PCI, target vessel failure, target lesion revascularization, renal failure requiring renal-replacement therapy, angiographic outcomes at 3-years and quality of life (delta Seattle Angina Questionnaire, Canadian Cardiovascular Society Grading Scale and Rose Dyspnea Scale). CONCLUSION: PROCTOR is the first randomized trial comparing an invasive strategy of native coronary artery PCI with SVG PCI in post-CABG patients presenting with SVG failure.

Collateral grading systems in retrograde percutaneous coronary intervention of chronic total occlusions.

BACKGROUND: The Japanese Channel (J-Channel) score was introduced to aid in retrograde percutaneous coronary intervention (PCI) of chronic total coronary occlusions (CTOs). The predictive value of the J-Channel score has not been compared with established collateral grading systems such as the Rentrop classification and Werner grade. AIMS: To investigate the predictive value of the J-Channel score, Rentrop classification and Werner grade for successful collateral channel (CC) guidewire crossing and technical CTO PCI success. METHODS: A total of 600 prospectively recruited patients underwent CTO PCI. All grading systems were assessed under dual catheter injection. CC guidewire crossing was considered successful if the guidewire reached the distal segment of the CTO vessel through a retrograde approach. Technical CTO PCI success was defined as thrombolysis in myocardial infarction flow grade 3 and residual stenosis <30%. RESULTS: Of 600 patients, 257 (43%) underwent CTO PCI through a retrograde approach. Successful CC guidewire crossing was achieved in 208 (81%) patients. The predictive value of the J-Channel score for CC guidewire crossing (area under curve 0.743) was comparable with the Rentrop classification (0.699, p = 0.094) and superior to the Werner grade (0.663, p = 0.002). Technical CTO PCI success was reported in 232 (90%) patients. The Rentrop classification exhibited a numerically higher discriminatory ability (0.676) compared to the J-Channel score (0.664) and Werner grade (0.589). CONCLUSIONS: The J-channel score might aid in strategic collateral channel selection during retrograde CTO PCI. However, the J-Channel score, Rentrop classification, and Werner grade have limited value in predicting technical CTO PCI success.

Coronary Collateral Flow Index Is Correlated With the Palmar Collateral Flow Index: Indicating Systemic Collateral Coherence in Individual Patients-Brief Report.

[Figure: see text].

Diagnostic and Management Strategies in Patients with Late Recurrent Angina after Coronary Artery Bypass Grafting.

PURPOSE OF REVIEW: This review will outline the current evidence on the anatomical, functional, and physiological tools that may be applied in the evaluation of patients with late recurrent angina after coronary artery bypass grafting (CABG). Furthermore, we discuss management strategies and propose an algorithm to guide decision-making for this complex patient population. RECENT FINDINGS: Patients with prior CABG often present with late recurrent angina as a result of bypass graft failure and progression of native coronary artery disease (CAD). These patients are generally older, have a higher prevalence of comorbidities, and more complex atherosclerotic lesion morphology compared to CABG-naïve patients. In addition, guideline recommendations are based on studies in which post-CABG patients have been largely excluded. Several invasive and non-invasive diagnostic tools are currently available to assess graft patency, the hemodynamic significance of native CAD progression, left ventricular function, and myocardial viability. Such tools, in particular the latest generation coronary computed tomography angiography, are part of a systematic diagnostic work-up to guide optimal repeat revascularization strategy in patients presenting with late recurrent angina after CABG.

Non-invasive procedural planning using computed tomography-derived fractional flow reserve.

OBJECTIVES: This study aimed to investigate the performance of computed tomography derived fractional flow reserve based interactive planner (FFRCT planner) to predict the physiological benefits of percutaneous coronary intervention (PCI) as defined by invasive post-PCI FFR. BACKGROUND: Advances in FFRCT technology have enabled the simulation of hyperemic pressure changes after virtual removal of stenoses. METHODS: In 56 patients (63 vessels) invasive FFR measurements before and after PCI were obtained and FFRCT was calculated using pre-PCI coronary CT angiography. Subsequently, FFRCT and invasive coronary angiography models were aligned allowing virtual removal of coronary stenoses on pre-PCI FFRCT models in the same locations as PCI was performed. Relationships between invasive FFR and FFRCT , between post-PCI FFR and FFRCT planner, and between delta FFR and delta FFRCT were evaluated. RESULTS: Pre PCI, invasive FFR was 0.65 ± 0.12 and FFRCT was 0.64 ± 0.13 (p = .34) with a mean difference of 0.015 (95% CI: -0.23-0.26). Post-PCI invasive FFR was 0.89 ± 0.07 and FFRCT planner was 0.85 ± 0.07 (p < .001) with a mean difference of 0.040 (95% CI: -0.10-0.18). Delta invasive FFR and delta FFRCT were 0.23 ± 0.12 and 0.21 ± 0.12 (p = .09) with a mean difference of 0.025 (95% CI: -0.20-0.25). Significant correlations were found between pre-PCI FFR and FFRCT (r = 0.53, p < .001), between post-PCI FFR and FFRCT planner (r = 0.41, p = .001), and between delta FFR and delta FFRCT (r = 0.57, p < .001). CONCLUSIONS: The non-invasive FFRCT planner tool demonstrated significant albeit modest agreement with post-PCI FFR and change in FFR values after PCI. The FFRCT planner tool may hold promise for PCI procedural planning; however, improvement in technology is warranted before clinical application.

Viability and functional recovery after chronic total occlusion percutaneous coronary intervention.

OBJECTIVES: This study evaluated myocardial viability as well as global and regional functional recovery after successful chronic coronary total occlusion (CTO) percutaneous coronary intervention (PCI) using sequential quantitative cardiac magnetic resonance (CMR) imaging. BACKGROUND: The patient benefits of CTO PCI are being questioned. METHODS: In a single high-volume CTO PCI center patients were prospectively scheduled for CMR at baseline and 3 months after successful CTO PCI between 2013 and 2018. Segmental wall thickening (SWT) and percentage late gadolinium enhancement (LGE) were quantitatively measured per segment. Viability was defined as dysfunctional myocardium (<2.84 mm SWT) with no or limited scar (≤50% LGE). RESULTS: A total of 132 patients were included. Improvement of left ventricular ejection fraction was modest after CTO PCI (from 48.1 ± 11.8 to 49.5 ± 12.1%, p < 0.01). CTO segments with viability (N = 216, [31%]) demonstrated a significantly higher increase in SWT (0.80 ± 1.39 mm) compared to CTO segments with pre-procedural preserved function (N = 456 [65%], 0.07 ± 1.43 mm, p < 0.01) or extensive scar (LGE >50%, N = 26 [4%], -0.08 ± 1.09 mm, p < 0.01). Patients with ≥2 CTO segments viability showed more SWT increase in the CTO territory compared to patients with 0-1 segment viability (0.49 ± 0.93 vs. 0.12 ± 0.98 mm, p = 0.03). CONCLUSIONS: Detection of dysfunctional myocardial segments without extensive scar (≤50% LGE) as a marker for viability on CMR aids in identifying patients with significant regional functional recovery after CTO PCI.

Residual Quantitative Flow Ratio to Estimate Post-Percutaneous Coronary Intervention Fractional Flow Reserve.

OBJECTIVES: Quantitative flow ratio (QFR) computes fractional flow reserve (FFR) based on invasive coronary angiography (ICA). Residual QFR estimates post-percutaneous coronary intervention (PCI) FFR. This study sought to assess the relationship of residual QFR with post-PCI FFR. METHODS: Residual QFR analysis, using pre-PCI ICA, was attempted in 159 vessels with post-PCI FFR. QFR lesion location was matched with the PCI location to simulate the performed intervention and allow computation of residual QFR. A post-PCI FFR < 0.90 was used to define a suboptimal PCI result. RESULTS: Residual QFR computation was successful in 128 (81%) vessels. Median residual QFR was higher than post-PCI FFR (0.96 Q1-Q3: 0.91-0.99 vs. 0.91 Q1-Q3: 0.86-0.96, p < 0.001). A significant correlation and agreement were observed between residual QFR and post-PCI FFR (R = 0.56 and intraclass correlation coefficient = 0.47, p < 0.001 for both). Following PCI, an FFR < 0.90 was observed in 54 (42%) vessels. Specificity, positive predictive value, sensitivity, and negative predictive value of residual QFR for assessment of the PCI result were 96% (95% confidence interval (CI): 87-99%), 89% (95% CI: 72-96%), 44% (95% CI: 31-59%), and 70% (95% CI: 65-75%), respectively. Residual QFR had an accuracy of 74% (95% CI: 66-82%) and an area under the receiver operating characteristic curve of 0.79 (95% CI: 0.71-0.86). CONCLUSIONS: A significant correlation and agreement between residual QFR and post-PCI FFR were observed. Residual QFR ≥ 0.90 did not necessarily commensurate with a satisfactory PCI (post-PCI FFR ≥ 0.90). In contrast, residual QFR exhibited a high specificity for prediction of a suboptimal PCI result.

Comparison between quantitative cardiac magnetic resonance perfusion imaging and [15O]H2O positron emission tomography.

PURPOSE: To compare cardiac magnetic resonance imaging (CMR) with [15O]H2O positron emission tomography (PET) for quantification of absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) in patients with coronary artery disease (CAD). METHODS: Fifty-nine patients with stable CAD underwent CMR and [15O]H2O PET. The CMR imaging protocol included late gadolinium enhancement to rule out presence of scar tissue and perfusion imaging using a dual sequence, single bolus technique. Absolute MBF was determined for the three main vascular territories at rest and during vasodilator stress. RESULTS: CMR measurements of regional stress MBF and MFR showed only moderate correlation to those obtained using PET (r = 0.39; P < 0.001 for stress MBF and r = 0.36; P < 0.001 for MFR). Bland-Altman analysis revealed a significant bias of 0.2 ± 1.0 mL/min/g for stress MBF and - 0.5 ± 1.2 for MFR. CMR-derived stress MBF and MFR demonstrated area under the curves of respectively 0.72 (95% CI: 0.65 to 0.79) and 0.76 (95% CI: 0.69 to 0.83) and had optimal cutoff values of 2.35 mL/min/g and 2.25 for detecting abnormal myocardial perfusion, defined as [15O]H2O PET-derived stress MBF ≤ 2.3 mL/min/g and MFR ≤ 2.5. Using these cutoff values, CMR and PET were concordant in 137 (77%) vascular territories for stress MBF and 135 (80%) vascular territories for MFR. CONCLUSION: CMR measurements of stress MBF and MFR showed modest agreement to those obtained with [15O]H2O PET. Nevertheless, stress MBF and MFR were concordant between CMR and [15O]H2O PET in 77% and 80% of vascular territories, respectively.

Continuous thermodilution to assess absolute flow and microvascular resistance: validation in humans using [15O]H2O positron emission tomography.

AIMS: Continuous thermodilution is a novel technique to quantify absolute coronary flow and microvascular resistance (MVR). Notably, intracoronary infusion of saline elicits maximal hyperaemia, obviating the need for adenosine. The primary aim of this study was to validate continuous thermodilution in humans by comparing invasive measurements to [15O]H2O positron emission tomography (PET). As a secondary goal, absolute flow and MVR were compared between invasive measurements obtained with and without adenosine. METHODS AND RESULTS: Twenty-five patients underwent coronary computed tomography angiography (CCTA), [15O]H2O PET, and invasive assessment. Absolute coronary flow and MVR were measured in the left anterior descending and left circumflex artery using a dedicated infusion catheter and a temperature/pressure sensor-tipped guidewire. Invasive measurements were performed with and without adenosine. In order to compare invasive flow measurements with PET perfusion, subtending myocardial mass of the investigated vessels was derived from CCTA using the Voronoi algorithm. Invasive and non-invasive measurements of adenosine-induced hyperaemic flow and MVR showed strong correlation (r = 0.91; P < 0.001 for flow and r = 0.85; P < 0.001 for MVR) and good agreement [intraclass correlation coefficient (ICC) = 0.90; P < 0.001 for flow and ICC = 0.79; P < 0.001 for MVR]. Absolute flow and MVR also correlated well between measurements with and without adenosine (r = 0.97; P < 0.001 for flow and r = 0.98; P < 0.001 for MVR) and showed good agreement (ICC = 0.96; P < 0.001 for flow and ICC = 0.98; P < 0.001 for MVR). CONCLUSIONS: Continuous thermodilution is an accurate method to measure absolute coronary flow and MVR, which is evidenced by strong agreement with [15O]H2O PET derived flow and resistance. Absolute flow and MVR correlate highly between invasive measurements obtained with and without adenosine, which confirms that intracoronary infusion of room temperature saline elicits steady-state maximal hyperaemia.

Recovery of myocardial perfusion after percutaneous coronary intervention of chronic total occlusions is comparable to hemodynamically significant non-occlusive lesions.

BACKGROUND: The benefits of chronic coronary total occlusion (CTO) percutaneous coronary intervention (PCI) are being questioned. The aim of this study was to assess the effects of CTO PCI on absolute myocardial perfusion, as compared with PCI of hemodynamically significant non-CTO lesions. METHODS: Consecutive patients with a preserved left ventricular ejection fraction (≥50%) and a CTO or non-CTO lesion, in whom [15 O]H2 O positron emission tomography was performed prior and after successful PCI, were included. Change in quantitative (hyperemic) myocardial blood flow (MBF), coronary flow reserve (CFR) and perfusion defect size (in myocardial segments) were compared between CTOs and non-CTO lesions. RESULTS: In total 92 patients with a CTO and 31 patients with a non-CTO lesion were included. CTOs induced larger perfusion defect sizes (4.51 ± 1.69 vs. 3.23 ± 2.38 segments, P < 0.01) with lower hyperemic MBF (1.30 ± 0.37 vs. 1.58 ± 0.62 mL·min-1 ·g-1 , P < 0.01) and similarly impaired CFR (1.66 ± 0.75 vs. 1.89 ± 0.77, P = 0.17) compared with non-CTO lesions. After PCI both hyperemic MBF and CFR increased similarly between groups (P = 0.57 and 0.35) to normal ranges with higher hyperemic MBF values in non-CTO compared with CTO (2.89 ± 0.94 vs. 2.48 ± 0.73 mL·min-1 ·g-1 , P = 0.03). Perfusion defect sizes decreased similarly after CTO PCI and non-CTO PCI (P = 0.14), leading to small residual defect sizes in both groups (1.15 ± 1.44 vs. 0.61 ± 1.45 segments, P = 0.054). CONCLUSIONS: Myocardial perfusion findings are slightly more hampered in patients with a CTO before and after PCI. Percutaneous revascularization of CTOs, however, improves absolute myocardial perfusion similarly to PCI of hemodynamically significant non-CTO lesions, leading to satisfying results.

Influence of pH and phosphate concentration on the phosphate binding capacity of five contemporary binders. An in vitro study.

AIM: Hyperphosphataemia is associated with increased mortality and morbidity in end stage renal disease. Despite phosphate binder therapy, a large proportion of patients do not reach the treatment target. In five contemporary binders we explored the influence of pH and phosphate concentration on phosphate binding. This interaction could be of relevance in clinical practice. METHODS: Phosphate binding was quantified in vitro in 25 mL of purified water containing phosphate concentrations of 10, 15 and 20 mM and baseline pH values of 3.0 or 6.0, with a binder over 6 h. Lanthanum carbonate, calcium acetate/magnesium carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide, 67 mg of each, were used. The experiments were performed in duplicate. The primary outcome was the difference in the amount of bound phosphate for each binder after 6 h in solutions at two different pH values. Secondary outcomes were the influence of phosphate concentration on phosphate binding, next to binding patterns and phosphate binder saturation. RESULTS AND CONCLUSION: In this specific in vitro setting, lanthanum carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide bound more phosphate in the solution with baseline pH of 3.0. Differences however were small except for lanthanum carbonate. Calcium acetate/magnesium carbonate was most effective in a solution with baseline pH of 6.0. All phosphate binders bound more phosphate in solutions with higher concentrations of phosphate. Sevelamer carbonate, calcium acetate/magnesium carbonate and sucroferric oxyhydroxide bound most phosphate in the first hour and reached maximum binding capacity in less than 6 h.

Subadventitial stenting around occluded stents: A bailout technique to recanalize in-stent chronic total occlusions.

OBJECTIVES: To evaluate the outcomes of subadventitial stenting (SS) around occluded stents for recanalizing in-stent chronic total occlusions (IS-CTOs). BACKGROUND: There is little evidence on the outcomes of SS for IS-CTO. METHODS: We examined the outcomes of SS for IS-CTO PCI at 14 centers between July 2011 and June 2017, and compared them to historical controls recanalized using within-stent stenting (WSS). Target-vessel failure (TVF) on follow-up was the endpoint of this study, and was defined as a composite of cardiac death, target-vessel myocardial infarction, and target-vessel revascularization. RESULTS: During study period, 422 IS-CTO PCIs were performed, of which 32 (7.6%) were recanalized with SS, usually when conventional approaches failed. The most frequent CTO vessel was the right coronary artery (72%). Mean J-CTO score was 3.1 ± 0.9. SS was antegrade in 53%, and retrograde in 47%. Part of the occluded stent was crushed in 37%, while the whole stent was crushed in 63%. Intravascular imaging was used in 59%. One patient (3.1%) suffered tamponade. Angiographic follow-up was performed in 10/32 patients: stents were patent in six cases, one had mild neointimal hyperplasia, and three had severe restenosis at the SS site. Clinical follow-up was available for 29/32 patients for a mean of 388 ± 303 days. The 24-month incidence of TVF was 13.8%, which was similar to historical controls treated with WSS (19.5%, P = 0.49). CONCLUSIONS: SS is rarely performed, usually as last resort, to recanalize complex IS-CTOs. It is associated with favorable acute and mid-term outcomes, but given the small sample size of our study additional research is warranted.

Hemodynamic Insights into Combined Fractional Flow Reserve and Instantaneous Wave-Free Ratio Assessment Through Quantitative [15O]H2O PET Myocardial Perfusion Imaging.

In patients evaluated for obstructive coronary artery disease (CAD), guidelines recommend using either fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) to guide coronary revascularization decision-making. The hemodynamic significance of lesions with discordant FFR and iFR measurements is debated. This study compared [15O]H2O PET-derived absolute myocardial perfusion between vessels with concordant and discordant FFR and iFR measurements. Methods: We included 197 patients suspected of obstructive CAD who had undergone [15O]H2O PET perfusion imaging and combined FFR/iFR interrogation in 468 vessels. Resting myocardial blood flow (MBF), hyperemic MBF, and coronary flow reserve (CFR) were compared among 4 groups: FFR low/iFR low (n = 79), FFR high/iFR low (n = 22), FFR low/iFR high (n = 22), and FFR high/iFR high (n = 345). Predefined [15O]H2O PET thresholds for ischemia were 2.3 mL·min-1·g-1 or less for hyperemic MBF and 2.5 or less for CFR. Results: Hyperemic MBF was lower in the concordant low (2.09 ± 0.67 mL·min-1·g-1), FFR high/iFR low (2.41 ± 0.80 mL·min-1·g-1), and FFR low/iFR high (2.40 ± 0.69 mL·min-1·g-1) groups compared with the concordant high group (2.91 ± 0.84 mL·min-1·g-1) (P < 0.001, P = 0.004, and P < 0.001, respectively). A lower CFR was observed in the concordant low (2.37 ± 0.76) and FFR high/iFR low (2.64 ± 0.84) groups compared with the concordant high group (3.35 ± 1.07, P < 0.01 for both). However, for vessels with either low FFR or low iFR, quantitative hyperemic MBF and CFR values exceeded the ischemic threshold in 38% and 49%, respectively. In addition, resting MBF exhibited a negative correlation with iFR (P < 0.001) and was associated with FFR low/iFR high discordance compared with concordant low FFR/low iFR measurements, independent of clinical and angiographic characteristics, as well as hyperemic MBF (odds ratio [OR], 0.41; 95% CI, 0.26-0.65; P < 0.001). Conclusion: We found reduced myocardial perfusion in vessels with concordant low and discordant FFR/iFR measurements. However, FFR/iFR combinations often inaccurately classified vessels as either ischemic or nonischemic when compared with hyperemic MBF and CFR. Furthermore, a lower resting MBF was associated with a higher iFR and the occurrence of FFR low/iFR high discordance. Our study showed that although combined FFR/iFR assessment can be useful to estimate the hemodynamic significance of coronary lesions, these pressure-derived indices provide a limited approximation of [15O]H2O PET-derived quantitative myocardial perfusion as the physiologic standard of CAD severity.

Impact of sex on myocardial perfusion following percutaneous coronary intervention of chronic total coronary occlusions.

OBJECTIVES: We sought to investigate the impact of sex on myocardial perfusion changes following chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) as measured by [15O]H2O positron-emission tomography (PET) perfusion imaging. BACKGROUND: CTO PCI has been associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization. As such, data on the impact of sex on myocardial perfusion following CTO PCI is scarce. METHODS: A total of 212 patients were prospectively enrolled and underwent CTO PCI combined with [15O]H2O PET perfusion imaging prior to and 3 months after PCI. Hyperemic myocardial blood flow (hMBF, mL·min-1·g-1) and coronary flow reserve (CFR) allocated to the CTO territory were quantitatively assessed. RESULTS: This study comprised 34 (16 %) females and 178 (84 %) males. HMBF at baseline did not differ between sexes. Females showed a higher increase in hMBF than males (Δ1.34 ± 0.67 vs. Δ1.06 ± 0.74, p = 0.044), whereas post-PCI hMBF was comparable (2.59 ± 0.85 in females vs. 2.28 ± 0.84 in males, p = 0.052). Female sex was independently associated with a higher increase in hMBF after correction for clinical covariates. CFR increase after revascularization was similar in females and males (Δ1.47 ± 0.99 vs. Δ1.30 ± 1.14, p = 0.711). CONCLUSIONS: The present study demonstrates a greater recovery of stress perfusion in females compared to males as measured by serial [15O]H2O PET imaging. In addition, a comparable increase in CFR was found in females and males. These results emphasize the benefit of performing CTO PCI in both sexes. CLINICAL PERSPECTIVE: What is new? What are the clinical implications?

Same-day discharge after large-bore access in percutaneous coronary intervention of chronic total coronary occlusions.

BACKGROUND: Same-day discharge (SDD) in patients undergoing percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) is appealing because of the increased patient comfort. However, data on SDD following large-bore vascular access are scarce. AIMS: We investigated the feasibility and safety of SDD in patients undergoing large-bore CTO PCI. METHODS: Between 2013 and 2023, 948 patients were prospectively enrolled in a single-centre CTO registry and underwent CTO PCI. SDD was pursued in all patients. Large-bore access was defined as the use of ≥7 French (Fr) sheaths in ≥1 access site. A logistic regression analysis was used to identify predictors for non-SDD. Clinical follow-up was obtained at 30 days. RESULTS: SDD was observed in 62% of patients. Large-bore access was applied in 99% of the cohort. SDD patients were younger and more often male, with lower rates of renal insufficiency and prior coronary artery bypass grafting. Local access site bleeding (odds ratio [OR] 8.53, 95% confidence interval [CI]: 5.24-13.87) and vascular access complications (OR 7.23, 95% CI: 1.98-26.32) made hospitalisation more likely, with vascular access complications occurring in 3%. At 30 days, the hospital readmission rate was low in both SDD and non-SDD patients (5% vs 7%; p=non-significant). Finally, SDD was not a predictor for major adverse cardiovascular events (MACE) at follow-up. CONCLUSIONS: Same-day discharge can be achieved in the majority of patients undergoing CTO PCI with large-bore (≥7 Fr) access. Similar low hospital readmission and MACE rates between SDD and non-SDD patients at 30 days demonstrate the feasibility and safety of SDD.

Computed tomography perfusion and angiography in patients with chronic total occlusion undergoing percutaneous coronary intervention.

BACKGROUND AND AIMS: Myocardial perfusion imaging (MPI) and anatomical imaging with coronary computed tomography angiography (CCTA) can play an important role in the preprocedural planning of a chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We aimed to establish the feasibility of a novel dynamic computed tomography perfusion (CTP) analysis for the assessment of myocardial perfusion before and after a successful recanalization of CTO in patients undergoing CCTA as part of a standard preprocedural workup. METHODS: In a prospective observational study symptomatic patients underwent dynamic CTP on a dual-source CT scanner both before and 3 months after successful CTO PCI. RESULTS: Twenty-seven patients completed the study (63 ± 8 years old, 78% male). Following successful CTO PCI, there was a significant reduction in the ischemic burden (5 [5-7] versus 1 [0-2] segments, p < 0.001), and improvement in myocardial blood flow (85.3 [71.7-94.1] versus 134.6 [123.8-156.9] mL/min, p < 0.001) resulting in an increase in the relative flow reserve (0.49 [0.41-0.57] versus 0.88 [0.74-0.95], p < 0.001). CONCLUSIONS: CTP emerges as a robust and safe method for MPI in CTO patients. The single imaging session assessment of both coronary anatomy and perfusion with CT lends itself to precise disease phenotyping in the challenging population of CTO patients.

Prognostic Value of Modified Coronary Flow Capacity Derived From [15O]H2O Positron Emission Tomography Perfusion Imaging.

BACKGROUND: Coronary flow capacity (CFC) is a measure that integrates hyperemic myocardial blood flow and coronary flow reserve to quantify the pathophysiological impact of coronary artery disease on vasodilator capacity. This study explores the prognostic value of modified CFC derived from [15O]H2O positron emission tomography perfusion imaging. METHODS: Quantitative rest/stress perfusion measurements were obtained from 1300 patients with known or suspected coronary artery disease. Patients were classified as having myocardial steal (n=38), severely reduced CFC (n=141), moderately reduced CFC (n=394), minimally reduced CFC (n=245), or normal flow (n=482) using previously defined thresholds. The end point was a composite of death and nonfatal myocardial infarction. RESULTS: During a median follow-up of 5.5 (interquartile range, 3.7-7.8) years, the end point occurred in 153 (12%) patients. Myocardial steal (hazard ratio [HR], 6.70 [95% CI, 3.21-13.99]; P<0.001), severely reduced CFC (HR, 2.35 [95% CI, 1.16-4.78]; P=0.018), and moderately reduced CFC (HR, 1.95 [95% CI, 1.11-3.41]; P=0.020) were associated with worse prognosis compared with normal flow, after adjusting for clinical characteristics. Similarly, in the overall population, increased resting myocardial blood flow (HR, 3.05 [95% CI, 1.68-5.54]; P<0.001), decreased hyperemic myocardial blood flow (HR, 0.68 [95% CI, 0.52-0.90]; P=0.007) and decreased coronary flow reserve (HR, 0.55 [95% CI, 0.42-0.71]; P<0.001) were independently associated with adverse outcome. In a model adjusted for the combined use of perfusion metrics, modified CFC demonstrated independent prognostic value (overall P=0.017). CONCLUSIONS: [15O]H2O positron emission tomography-derived resting myocardial blood flow, hyperemic myocardial blood flow, coronary flow reserve, and CFC are prognostic factors for death and nonfatal myocardial infarction in patients with known or suspected coronary artery disease. Importantly, after adjustment for clinical characteristics and the combined use of [15O]H2O positron emission tomography perfusion metrics, modified CFC remained independently associated with adverse outcome.

The diagnostic performance of quantitative flow ratio and perfusion imaging in patients with prior coronary artery disease.

AIMS: In chronic coronary syndrome (CCS) patients with documented coronary artery disease (CAD), ischaemia detection by myocardial perfusion imaging (MPI) and an invasive approach are viable diagnostic strategies. We compared the diagnostic performance of quantitative flow ratio (QFR) with single-photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance imaging (CMR) in patients with prior CAD [previous percutaneous coronary intervention (PCI) and/or myocardial infarction (MI)]. METHODS AND RESULTS: This PACIFIC-2 sub-study evaluated 189 CCS patients with prior CAD for inclusion. Patients underwent SPECT, PET, and CMR followed by invasive coronary angiography with fractional flow reserve (FFR) measurements of all major coronary arteries (N = 567), except for vessels with a sub-total or chronic total occlusion. Quantitative flow ratio computation was attempted in 488 (86%) vessels with measured FFR available (FFR ≤0.80 defined haemodynamically significant CAD). Quantitative flow ratio analysis was successful in 334 (68%) vessels among 166 patients and demonstrated a higher accuracy (84%) and sensitivity (72%) compared with SPECT (66%, P < 0.001 and 46%, P = 0.001), PET (65%, P < 0.001 and 58%, P = 0.032), and CMR (72%, P < 0.001 and 33%, P < 0.001). The specificity of QFR (87%) was similar to that of CMR (83%, P = 0.123) but higher than that of SPECT (71%, P < 0.001) and PET (67%, P < 0.001). Lastly, QFR exhibited a higher area under the receiver operating characteristic curve (0.89) than SPECT (0.57, P < 0.001), PET (0.66, P < 0.001), and CMR (0.60, P < 0.001). CONCLUSION: QFR correlated better with FFR in patients with prior CAD than MPI, as reflected in the higher diagnostic performance measures for detecting FFR-defined, vessel-specific, significant CAD.

Feasibility of computed tomography perfusion in patients with chronic total occlusion undergoing percutaneous coronary intervention.

We aimed to establish the feasibility and safety of dynamic computed tomography perfusion (CTP) in patients with chronic total occlusion (CTO) undergoing percutaneous coronary intervention (PCI). Ten consecutive CTO patients with preserved left ventricular ejection fraction (≥50%) underwent regadenoson dynamic CTP prior to and at least 3 months after successful CTO recanalization. Quantitative absolute and indexed values of stress myocardial blood flow (MBF) were measured for each myocardial segment, and perfusion defect size was defined by the number of segments with indexed MBF ≤0.78. The control group comprised 10 subjects without ischemia on CTP. Out of 20 CTP studies with 320 segments, 311 segments (97.2%) were interpretable. The dose-length product for CTP was 589.5 â€‹± â€‹144.3 mGy cm, and no severe adverse reactions to either regadenoson or contrast were observed. Successful PCI resulted in a significant increase in stress MBF in CTO (101.8 [82.9-127.1] vs. 158.4 [132.6-172] ml/100ml/min, p â€‹= â€‹0.004). Overall, there were significant reductions in both CTO and total defect size post-PCI (5 [5-6] vs. 1 [0.3-2] and 6 [5-8.5] vs. 1.5 [1-3.8] segments, both p â€‹= â€‹0.002). In segment analysis, the indexed MBF was lowest in the pre-PCI CTO group (0.90 [0.53-1.0]), followed by post-PCI CTO group (0.96 [0.88-1.0]) and the control group (0.98 [0.94-1.0]). Dynamic CTP is feasible and safe, and shows large perfusion defects in patients with CTO. While ischemic burden can be significantly improved after successful CTO PCI, it is still larger as compared with normal myocardium. NCT04465526: The Influence of Coronary Chronic Total Occlusion on Myocardial Perfusion on Computed Tomography (COPACABANA).

The impact of coronary revascularization on vessel-specific coronary flow capacity and long-term outcomes: a serial [15O]H2O positron emission tomography perfusion imaging study.

AIMS: Coronary flow capacity (CFC) integrates quantitative hyperaemic myocardial blood flow (hMBF) and coronary flow reserve (CFR) to comprehensively assess physiological severity of coronary artery disease (CAD). This study evaluated the effects of revascularization on CFC as assessed by serial [15O]H2O positron emission tomography (PET) perfusion imaging. METHODS AND RESULTS: A total of 314 patients with stable CAD underwent [15O]H2O PET imaging at baseline and after myocardial revascularization to assess changes in hMBF, CFR, and CFC in 415 revascularized vessels. Using thresholds for ischaemia and normal perfusion, vessels were stratified in five CFC categories: myocardial steal, severely reduced CFC, moderately reduced CFC, minimally reduced CFC, and normal flow. Additionally, the association between CFC increase and the composite endpoint of death and non-fatal myocardial infarction (MI) was studied. Vessel-specific CFC improved after revascularization (P < 0.01). Furthermore, baseline CFC was an independent predictor of CFC increase (P < 0.01). The largest changes in ΔhMBF (0.90 ± 0.74, 0.93 ± 0.65, 0.79 ± 0.74, 0.48 ± 0.61, and 0.29 ± 0.66 mL/min/g) and ΔCFR (1.01 ± 0.88, 0.99 ± 0.69, 0.87 ± 0.88, 0.66 ± 0.91, and -0.01 ± 1.06) were observed in vessels with lower baseline CFC (P < 0.01 for both). During a median follow-up of 3.5 (95% CI 3.1-3.9) years, an increase in CFC was independently associated with lower rates of death and non-fatal MI (HR 0.43, 95% CI 0.19-0.98, P = 0.04). CONCLUSION: Successful revascularization results in an increase in CFC. Furthermore, baseline CFC was an independent predictor of change in hMBF, CFR, and subsequently CFC. In addition, an increase in CFC was associated with a favourable outcome in terms of death and non-fatal MI.