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Background: Fractional flow reserve (FFR) has emerged as the invasive gold standard for assessing vessel-specific ischemia. However, FFR measurements are influenced by the hydrostatic effect, which might adversely impact the assessment of ischemia., Aims: This study aimed to investigate the impact of hydrostatic pressure on FFR measurements by correcting for the height and comparing FFR with [ 15 O]H 2 O positron emission tomography (PET)-derived relative flow reserve (RFR)., Methods: The 206 patients were included in this analysis. Patients underwent coronary computed tomography angiography (CCTA), [ 15 O]H 2 O PET, and invasive coronary angiography with routine FFR in every epicardial artery. Height differences between the aortic guiding catheter and distal pressure sensor were quantified on CCTA images. An FFR ≤ 0.80 was considered significant., Results: The study found a reclassification in 7% of the coronary arteries. Notably, 11% of left anterior descending (LAD) arteries were reclassified from hemodynamically significant to nonsignificant. Conversely, 6% of left circumflex (Cx) arteries were reclassified from nonsignificant to significant. After correcting for the hydrostatic pressure effect, the correlation between FFR and PET-derived RFR increased significantly from r = 0.720 to r = 0.786 (p = 0.009). The average magnitude of correction was +0.05 FFR units in the LAD, -0.03 in the Cx, and -0.02 in the right coronary artery., Conclusion: Hydrostatic pressure has a small but clinically relevant influence on FFR measurements obtained with a pressure wire. Correcting for this hydrostatic error significantly enhances the correlation between FFR and PET-derived RFR., (© 2024 The Author(s). Catheterization and Cardiovascular Interventions published by Wiley Periodicals LLC.)

When measuring hyperemic and nonhyperemic pressure ratios with traditional sensor-tipped wires, the inevitable hydrostatic pressure gradient (HPG) may influence treatment decisions. This study aimed to simulate and analyze the effect of a hydrostatic pressure gradient on different indices of functional lesion severity. A hypothetical P d -P a height difference and subsequent hydrostatic pressure gradient based on previous literature was applied to the pressure measurements from the CONTRAST study. The effect on three indices of functional lesion severity (FFR, P d /P a , and dPR) was assessed and possible reclassifications in functional significance by the different indices were analyzed. In 602 pressure tracings, simulated hydrostatic pressure gradients led to an absolute change in P d of 3.18 ± 1.30 mmHg, resulting in an overall increase in FFR, P d /P a, and dPR of 0.02 ± 0.04 for all indices ( P = 0.69). Reclassification due to the hydrostatic pressure gradient when using dichotomous cutoff values occurred in 13.4, 22.3, and 20.6% for FFR, P d /P a , and dPR, respectively. The effect of hydrostatic pressure gradient correction differed among the coronary arteries and was most pronounced in the left anterior descending. When considering the gray zone for the different functional indices, the hydrostatic pressure gradient resulted in reclassification in only one patient out of the complete patient population (1/602; 0.17%). The hydrostatic pressure gradient can influence functional lesion assessment when using dichotomous cutoff values. When taking the gray zone into account, its effect is limited. NEW & NOTEWORTHY This study systematically simulated the effect of hydrostatic pressure gradients (HPG) on real-world hyperemic and nonhyperemic pressure ratios, showing correction for HPG leads to reclassification in functional significance from 13.4 to 22.3% for different functional indices. This was most pronounced in nonhyperemic pressure ratios. A new pressure guidewire (Wirecath) is unaffected by HPG. The ongoing PW-COMPARE study (NCT04802681) prospectively analyzes the magnitude and importance of HPG by simultaneous FFR measurements.

Objectives: This study aimed to prospectively investigate intra-aortic balloon pump counterpulsation (IABP) support in large myocardial infarction complicated by persistent ischemia after primary percutaneous coronary intervention (PCI)., Background: Use of IABP is suggested to be effective by increasing diastolic aortic pressure, thereby improving coronary blood flow. This can only be expected with exhausted coronary autoregulation, typical in acute myocardial infarction complicated by persistent ischemia. In this situation, augmented diastolic pressure is expected to increase myocardial oxygenation., Methods: One hundred patients with large STEMI complicated by persistent ischemia after primary PCI were randomized to treatment with or without IABP therapy on top of standard care. IABP support was initiated following primary PCI, immediately after inclusion. Primary end point was all-cause mortality, need for (additional) mechanical hemodynamic support, or readmission for heart failure within 6 months., Results: Mean age was 63 ± 10 years, 76% were male. Mean systolic and diastolic blood pressure were 120 ± 25 mmHg and 73 ± 17 mmHg. Mean heart rate was 75 ± 18 mmHg. Before PCI, mean summed ST-deviation was 21 ± 8 mm with only minimal ST-resolution after PCI. One patient in the IABP group reached the primary end point versus four patients in the control group (2% vs. 8%; p = 0.16). After primary PCI, resolution of ST-deviation was significantly more pronounced in the IABP group (73 ± 17%) compared to the control group (56 ± 26%; p < 0.01)., Conclusions: In this pilot study, in patients with large STEMI and persistent ischemia after primary PCI, use of IABP showed a nonsignificant decrease in mortality, necessity for (additional) mechanical hemodynamic support or readmission for heart failure at 6 months, and resulted in more rapid ST-resolution., (© 2019 Wiley Periodicals, Inc.)

Background: Pressure measurement for the duration of the wave-free period (WFP) is considered essential for resting-state physiological assessment of coronary stenosis severity using the instantaneous wave-free ratio (iFR)., Objectives: The aim of this study was to compare other diastolic resting indexes to iFR., Methods: In the population of the VERIFY2 (Pd/Pa vs iFR in an Unselected Population Referred for Invasive Angiography) study, iFR calculated by proprietary software (Volcano Harvest, Volcano Corporation, Rancho Cordova, California) was compared with the ratio of resting distal coronary pressure and aortic pressure during the complete duration of diastole (dPR), 25% to 75% of diastole (dPR 25-75 ), and midpoint of diastole (dPR mid ), along with Matlab calculated iFR (iFR matlab ) and iFR-like indexes shortening the length of the WFP by 50 and 100 ms (iFR -50ms and iFR -100ms ), respectively. Mutual differences, Spearman correlations, area under the curve values from receiver-operating characteristic analyses, and diagnostic performance with respect to iFR and fractional flow reserve (FFR) were calculated for all indexes., Results: Median iFR in 197 patients with 257 vessels was 0.91 with an interquartile range of 0.87 to 0.95. The mutual differences (± SD) with iFR were 0.006 ± 0.011 (dPR), 0.001 ± 0.007 (dPR 25-75 ), 0.001 ± 0.008 (dPR mid ), 0.005 ± 0.009 (iFR matlab ), 0.003 ± 0.008 (iFR -50ms ), and 0.001 ± 0.009 (iFR -100ms ). Correlations for all indexes with iFR were >0.99 (p < 0.001 for all). Area under the curve values for predicting iFR were >0.99 for all indexes as well. Diagnostic accuracy compared with FFR was 76% to 77% for all indexes including iFR., Conclusions: All diastolic resting indexes tested were identical to iFR, both numerically and with respect to their agreement with FFR. A numerically equal value to iFR can be determined without restriction to the WFP. Cutoff values, guidelines, and clinical recommendations for iFR can therefore be extended to these other indexes. (Pd/Pa vs iFR in an Unselected Population Referred for Invasive Angiography [VERIFY2]; NCT02377310)., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Hypothermia may attenuate reperfusion injury and thereby improve acute myocardial infarction therapy. Systemic cooling trials failed to reduce infarct size, perhaps because the target temperature was not reached fast enough. The use of selective intracoronary hypothermia combined with intracoronary temperature monitoring allows for titrating to target temperature and optimizing the cooling rate. We aimed to the test the feasibility of intracoronary cooling for controlled, selective myocardial hypothermia in an isolated beating pig heart. In five porcine hearts the left anterior descending artery (LAD) was occluded by an over-the-wire balloon (OTWB). After occlusion, saline at 22°C was infused through the OTWB lumen for 5 minutes into the infarct area at a rate of 30 ml/min. Thereafter the balloon was deflated but infusion continued with saline at 4°C for 5 minutes. Distal coronary temperature was continuously monitored by a pressure/temperature guidewire. Myocardial temperature at several locations in the infarct and control areas was recorded using needle thermistors. In the occlusion phase, coronary temperature decreased by 11.4°C (range 9.4-12.5°C). Myocardial temperature throughout the infarct area decreased by 5.1°C (range 1.8-8.1°C) within three minutes. During the reperfusion phase, coronary temperature decreased by 6.2°C (range 4.1-10.3°C) and myocardial temperature decreased by 4.5°C (range 1.5-7.4°C). Myocardial temperature outside the infarct area was not affected. In the isolated beating pig heart with acute occlusion of the LAD, we were able to rapidly "induce, maintain, and control" a stable intracoronary and myocardial target temperature of at least 4°C below body temperature without side effects and using standard PCI equipment, justifying further studies of this technique in humans.