Microcirculatory significance of periprocedural myocardial necrosis after percutaneous coronary intervention assessed by the index of microcirculatory resistance

The coronary angiography-derived index of microcirculatory resistance predicts perioperative myocardial injury in stable coronary artery disease patients undergoing PCI

Background

Coronary microvascular dysfunction (CMD) assessed by the index of microcirculatory resistance (IMR) is associated with perioperative myocardial injury (PMI).The angiographically derived index of microcirculatory resistance (caIMR) represents a novel and accurate alternative to IMR.

Objective

This study aims to evaluate the predictive ability of caIMR for PMI in patients with stable coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI).

Methods

Consecutive patients with stable CAD undergoing elective PCI of a single lesion were recruited. caIMR was measured before and after revascularisation, and total creatine kinase-MB (CK-MB) and high-sensitivity troponin T (hsTnT) levels were measured before and within 24 h after PCI.

Results

A total of 65 patients were enrolled and 26 patients fulfilled the diagnostic criteria for PMI. Post-PCI caIMR values were significantly higher in the PMI group than in the control group (27.02 ± 3.70 vs. 15.91 ± 3.43U, P < 0.001). Pearson correlation analysis showed that increased post-PCI caIMR values had a significant positive correlation with peak hsTnT (r = 0.803, P < 0.001) and peak CK-MB (r = 0.512, P = 0.001). Multivariate logistic regression analysis showed that post-PCI caIMR was an independent predictor of PMI (OR,1.731; 95 % CI:1.348-2.023; P < 0.001).ROC analysis suggested that the best cut-off value of post-PCI caIMR was 25.17U to diagnose PMI (AUC = 0.951, sensitivity 88.5 %, specificity 97.1 %). During a median follow-up 16 months, patients with PMI had a higher incidence of major adverse cardiovascular events (MACE) (42.31 % vs 5.13 %, P = 0.04).

Conclusions

Post-PCI caIMR can accurately predict PMI and clinical outcomes in stable CAD patients undergoing elective PCI, which supports the use of caIMR in clinical practice.

The Role of Index of Microcirculatory Resistance in Left Anterior Descending Artery ST Segment Elevation Myocardial Infarction Patients after Primary Percutaneous Coronary Intervention

Background: Our aim was to assess the relationship of the index of microvascular resistance (IMR) in left anterior descending (LAD) artery involved STEMI patients. Methods: Data of 316 STEMI patients who had undergone primary percutaneous coronary intervention (PCI) were collected from three cardiovascular centers from 2005 to 2015. In total, 246 patients with LAD STEMI were enrolled for IMR evaluation. Patients were divided into two groups respective of the cut-off IMR value of 30. All-cause mortality, left ventricular function, improvement of systolic function, and cardiac biomarkers were analyzed and compared. Results: A total of 246 patients were enrolled. The number of patients in the IMR above 30 group was 93 and below 30 was 153. The mean ages for each group were 57.91 ± 11.99 and 54 ± 10.63, respectively. The peak creatinine kinase (CK) (3936.85 ± 2827.32 IU/L vs. 2218.08 ± 2310.41 IU/L, p < 0.001) and CKmb (336.15 ± 195.08 mg/mL vs. 231.53 ± 179.53 mg/mL, p < 0.001) levels were higher for an IMR above the 30 group. The left ventricular ejection fraction (LVEF) (44.57 ± 6.685% vs. 47.35 ± 8.17%, p = 0.006) and improvement of LVEF (2.81 ± 7.135% vs. 5.88 ± 7.65%, p = 0.004) was lower in the IMR above 30 group. All-cause mortality (7.5% vs. 1.3%, p = 0.012) was higher in the IMR above 30 group, and a Cox regression analysis showed that an IMR above 30 was a poor prognostic factor regarding all-cause mortality (HR: 5.151, 95% CI 1.062-24.987, p = 0.042) even after adjusting for classical clinical risk factors. Conclusions: An elevated IMR value represented larger infarct size, more severe LV dysfunction, and higher mortality in LAD STEMI patients after successful PCI.

COlchicine to Prevent PeriprocEdural Myocardial Injury in Percutaneous Coronary Intervention (COPE-PCI): Coronary Microvascular Physiology Pilot Substudy

Aim

In this randomized pilot trial, we aimed to assess the anti-inflammatory effect of preprocedural colchicine on coronary microvascular physiology measurements before and after PCI.

Methods

Patients undergoing PCI for stable angina (SA) or non-ST-elevation myocardial infarction (NSTEMI) were randomized to oral colchicine or placebo, 6- to 24-hours before the procedure. Strict prespecified inclusion/exclusion criteria were set to ensure all patients were given the study medication, had a PCI, and had pre- and post-PCI culprit vessel invasive coronary physiology measurements. Fractional flow reserve (FFR), Index of Microvascular Resistance (IMR), Coronary Flow Reserve (CFR), and Resistive Reserve Ratio (RRR) were measured immediately before and after PCI. CMVD was defined as any one of post-PCI IMR >32 or CFR <2 or RRR <2. High-sensitive-(hs)-troponin-I, hsCRP, and leucocyte count were measured before and 24 hours after PCI.

Results

A total of 50 patients were randomized and met the strict prespecified inclusion/exclusion criteria: 24-colchicine and 26-placebo. Pre-PCI coronary physiology measurements, hs-troponin-I, and hsCRP were similar between groups. Although numerically lower in patients given colchicine, the proportion of patients who developed CMVD was not significantly different between groups (colchicine: 10 (42%) vs placebo: 16 (62%), p=0.16). Colchicine patients had higher post-PCI CFR and RRR vs placebo (respectively: 3.25 vs 2.00, p=0.03 & 4.25 vs 2.75, p < 0.01). Neutrophil count was lower after PCI in the colchicine arm (p=0.02), and hsCRP post-PCI remained low in both treatment arms (1.0 mg/L vs 1.7 mg/L, p=0.97). Patients randomized to colchicine had significantly less PCI-related absolute hs-troponin-I change (46 ng/L vs 152 ng/L, p=0.01).

Conclusion

In this pilot randomized substudy, colchicine given 6 to 24 hours before PCI did not statistically impact the post-PCI CMVD definition used in this study, yet it did improve post-PCI RRR and CFR measurements, with less procedure-related troponin release and less inflammation.

Effects of Danhong Injection () on Peri-Procedural Myocardial Injury and Microcirculatory Resistance in Patients with Unstable Angina Undergoing Elective Percutaneous Coronary Intervention: A Pilot Randomized Study

OBJECTIVE

To evaluate the effect of Danhong Injection (, DH) on the index of microcirculatory resistance (IMR) and myocardial injury in patients with unstable angina undergoing elective percutaneous coronary intervention (PCI).

METHODS

Seventy-eight patients with unstable angina were randomly divided into DH group (39 cases) and the control group (39 cases) during elective PCI. Randomization was performed using a random-number table. The DH group received DH at a dosage of 40 mL (mixed with 250 mL saline, covered by a light-proof bag, intravenous drip) during PCI and daily for 7 consecutive days, while the control group only received the same dosage of saline. Both groups received standardized treatment. The IMR and fractional flow reserve (FFR) were measured at maximal hyperemia before and after PCI. Myocardial markers, including myoglobin, creatine kinase (CK), creatine kinase MB (CK-MB), and coronary troponin T (cTnT) values were measured at baseline and 24 h after PCI.

RESULTS

Among the 78 patients enrolled, the baseline and procedural characteristics were similar between the two groups. There was no significant difference in pre-PCI myocardial markers and coronary physiological indexes between the two groups. However, post-PCI CK and CK-MB levels in the DH group were significantly lower than those in the control group (111.97 ± 80.97 vs. 165.47 ± 102.99, P=0.013; 13.08 ± 6.90 vs. 19.75 ± 15.49, P=0.016). Post-PCI myoglobin and cTNT-positive tend to be lower in the DH group than in the control group but did not reach statistical significance (88.07 ± 52.36 vs. 108.13 ± 90.94, P=0.52; 2.56% vs.7.69%, P=0.065). Compared with the control group, the post-IMR levels of the DH group tended to decrease, but there was no statistical difference (20.73 ± 13.15 vs. 26.37 ± 12.31, P=0.05). There were no statistical differences in post-FFR in both groups. The peri-procedural myocardial injury of the DH group was significantly lower than that of the control group (2.56% vs. 15.38%, P=0.025). During the 30-d follow-up period, no major adverse cardiovascular events occurred in either group.

CONCLUSION

This study demonstrated benefit of DH in reducing myocardial injury and potential preserving microvascular function in patients with unstable angina undergoing elective PCI.

Periprocedural Myocardial Injury: Pathophysiology, Prognosis, and Prevention

The definition and clinical implications of myocardial infarction occurring in the setting of percutaneous coronary intervention have been the subject of unresolved controversy. The definitions of periprocedural myocardial infarction (PMI) are many and have evolved over recent years. Additionally, the recent advancement of different imaging modalities has provided useful information on a patients' pre-procedural risk of myocardial infarction. Nonetheless, questions on the benefit of different approaches to prevent PMI and their practical implementation remain open. This review aims to address these questions and to provide a current and contemporary perspective.

Different Microcirculation Response Between Culprit and Non-Culprit Vessels in Patients With Acute Coronary Syndrome

Background

This study investigated whether the microvascular dysfunction differed between culprit and non‐culprit vessels in patients with acute coronary syndrome who underwent percutaneous coronary intervention.

Methods and Results

In 115 prospectively recruited patients, after successful percutaneous coronary intervention, culprit and non‐culprit intracoronary hemodynamic measurements were performed and repeated at 6‐month follow‐up. ¹³N‐ammonia positron emission tomography was performed at 6‐month follow‐up visit to determine absolute myocardial blood flow. The resistance values of each vessel were calculated using the coronary pressure data and the myocardial blood flow values obtained from ¹³N‐ammonia positron emission tomography data. We compared the measurements between culprit and non‐culprit vessels and assessed changes in microvascular dysfunction during the study period. In 334 vessels (115 culprit and 219 non‐culprit), the culprit vessel group showed a lower fractional flow reserve and coronary flow reserve than the non‐culprit vessel group at baseline and 6‐month follow‐up, respectively. The value of index of microcirculatory resistance was different between the 2 groups in the baseline but not at 6‐month follow‐up. The microvascular resistance at rest and hyperemic microvascular resistance were not different between the 2 groups, but resistance to stenosis was higher in the culprit vessel group, under both resting and hyperemic status (P=0.02 and P<0.01, respectively). In the culprit vessel analysis, the fractional flow reserve and index of microcirculatory resistance decreased whereas coronary flow reserve increased (P<0.01 for all) at 6‐month follow‐up. However, there was no change in index of microcirculatory resistance, coronary flow reserve, and fractional flow reserve from baseline to 6‐month follow‐up in the non‐culprit vessel analysis.

Conclusions

The observed microvascular dysfunction in acute coronary syndrome is limited to the culprit vessel territory in the acute phase, which is relatively recovered in the chronic phase and there is no out‐of‐culprit territory involvement.

Registration

URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT04169516.

Intraluminal Intensity of Blood Speckle on Intravascular Ultrasound, a Novel Predictor of Periprocedural Myocardial Injury After Coronary Stenting

The difference in the intraluminal intensity of blood speckle (IBS) on integrated backscatter-intravascular ultrasound (IB-IVUS) across a coronary artery stenosis (i.e., ΔIBS) has previously shown a negative correlation with fractional flow reserve, reflecting an impaired coronary blood flow. Periprocedural myocardial injury (PMI) after coronary stenting has also been associated with coronary circulatory dysfunction. The aim of this study was to investigate the relation between ΔIBS after coronary stenting and PMI. A total of 180 patients who underwent elective coronary stenting under IVUS guidance for a single lesion were included. Intraluminal IBS was measured using IB-IVUS in cross sections at the ostium of the target vessel and at the distal reference of the stent. ΔIBS was calculated as (distal IBS value) - (ostium IBS value). PMI was defined as an elevation of troponin I >5 times the 99th percentile upper reference limit (>0.45 ng/ml) within 24 hours after the procedure. The mean ΔIBS after coronary stenting was 6.52 ± 5.71. There was a significantly greater use of the rotational atherectomy, the number of stents, the total stent length, and ΔIBS in patients with PMI than those without. In the receiver operating characteristic curve analysis, ΔIBS significantly predicted PMI (area under the curve 0.64, best cut-off value 7.88, p = 0.001). Multiple logistic regression analysis determined that the total stent length, the use of rotational atherectomy, and ΔIBS were independent predictors of PMI. In conclusion, greater ΔIBS assessed by IB-IVUS was significantly associated with PMI after coronary stenting in patients with a stable coronary artery disease.

Multi-detector CT and MRI of microembolized myocardial infarct: monitoring of left ventricular function, perfusion, and myocardial viability in a swine model

BACKGROUND

Patients with acute myocardial infarct (MI) show additional damage after coronary interventions.

PURPOSE

To longitudinally quantify structural and functional changes in the left ventricle (LV) subjected to microembolized MI using multidisciplinary computed tomography (MDCT) and independent reference methods.

MATERIAL AND METHODS

Swine (n = 20) served as controls (group I) or were subjected to a combination of coronary occlusion, microembolization, and reperfusion and imaged at 3 days (group II) or 3 days and 5 weeks (group III). LV volumes, perfusion, and MI mass were quantified on cine, perfusion, and delayed contrast enhancement (DE) MDCT. MRI, cardiac injury biomarkers, histochemical and histopathologic stains were used as independent references.

RESULTS

MDCT showed a reduction in ejection fraction and increased end systolic volume (31 ± 2% and 82 ± 3 mL, respectively) of group III compared with I (48 ± 2% and 57 ± 1 mL, respectively). It also demonstrated perfusion deficits in microembolized MI and peri-infarcts. DE-MDCT delineated microvascular obstruction (MVO) zones embedded in acute microembolized MI and microinfarct specks resulting from persistent MVO by deposited microemboli in microvessels of peri-infarct zone. Bland-Altman test showed close agreements between the extents of microembolized MI measured on DE-MDCT, DE-MRI, and histochemical TTC staining, but not between these modalities and microscopy. MI resorption was evident between 3 days and 5 weeks (13.4 ± 0.5 g and 9.8 ± 0.5 g, P < 0.017) and histologic examination revealed incomplete healing. Injury biomarkers were increased after intervention.

CONCLUSION

MDCT can longitudinally quantify regional perfusion deficits, LV dysfunction, and resorption of microembolized MI. MDCT or MRI can be used alternatively after coronary interventions in cases of contraindications for one modality or the other.

Determination of culprit coronary artery branches using hemodynamic indices from angiographic images

A recently reported angiographic technique for hemodynamic indices based on first-pass distribution analysis (FPA) could potentially be helpful for determining the culprit artery responsible for myocardial ischemia. The purpose of this study was to determinate the culprit coronary arterial branches based on coronary flow reserve (CFR) and fractional flow reserve (FFR) using only angiographic images. The study was performed in 14 anesthetized swine. Microspheres were injected into coronary arterial branches to create microvascular disruption. Stenosis was also created by inserting plastic tubings in LAD and LCX arterial branches. Adenosine was used to produce maximum hyperemia. Angiographic CFR (CFRa), relative angiographic CFR (rCFRa), and angiographic FFR (FFRa) were calculated by FPA. The diagnostic abilities of CFRa, rCFRa, and FFRa were compared in three models: (1) epicardial stenosis model (S), (2) microcirculation disruption model (M), and (3) combined(S + M) model by using the area under the ROC curve (AUC). The mean differences between FFRa and the pressure-derived FFR (FFRp) measurements were -0.01 ± 0.21 in S model (N = 37) and 0.01 ± 0.18 in M model (N = 53). From 225 measurements in S model, the AUCs for CFRa and FFRa were 0.720 and 0.918, respectively. From 262 measurements in M model and 238 measurements in (S + M) model, the AUCs for CFRa, rCFRa, FFRa were 0.744, 0.715, 0.959 and 0.806, 0.738, 0.995, respectively. The hemodynamic indices of the small branches (down to ~0.7 mm) could be measured using only angiographic image data. The application of FFRa could potentially provide a useful method to assess the severity of disease in coronary arterial branches.