Thrombus Aspiration in Primary Angioplasty for ST-segment Elevation Myocardial Infarction

A randomized controlled clinical trial of prolonged balloon inflation during stent deployment strategy in primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: a pilot study

Background

Primary percutaneous coronary intervention (PPCI) is the standard procedure for reperfusion for ST-segment elevation myocardial infarction (STEMI), but the occurrence of the no-reflow phenomenon remains common and is associated with adverse outcomes.

Aims

This study aimed to evaluate whether prolonged balloon inflation in stent deployment would lessen the occurrence of the no-reflow phenomenon in PPCI compared with conventional rapid inflation/deflation strategy.

Methods

Patients were randomly assigned to either the prolonged balloon inflation in stent deployment group (PBSG) or conventional deployment strategy group (CDSG) in a 1:1 ratio. A subset of patients was included in the cardiac magnetic resonance (CMR) assessment.

Results

Thrombolysis in MI (TIMI) flow grade 3 was found in 96.7% and 63.3% of the patients of the PBSG and CDSG, respectively (P = 0.005). The results of the PBSG and CDSG are respectively shown as follows: 0% versus 30% no-reflow or slow flow (P = 0.002); 90% versus 66.7% ST-segment resolution ≥ 50% (P = 0.028); 35.6 ± 14.5 frames versus 49.18 ± 25.2 frames on corrected TIMI frame count (P = 0.014); and 60% versus 20% myocardial blush grade 3 (P = 0.001). At 1 month, the major cardiovascular adverse event (cardiovascular mortality) rate was 3.3% in both groups; at 1 year, the rate was 3.3% and 6.7% for the PBSG and CDSG, respectively (P = 1.00). In the CMR subset of cases, the presence of microvascular obstruction (MVO) was detected in 6.7% and 50% of the patients in the PBSG and CDSG, respectively (P = 0.023).

Conclusion

In our pilot trial, prolonged balloon inflation during stent deployment strategy in PPCI reduces the occurrence of the no-reflow phenomenon in patients with STEMI and improved the myocardial microcirculation perfusion (ClinicalTrials.gov number: NCT03199014; registered: 26/June/2017).

Thrombus aspiration during primary percutaneous coronary intervention associated with reduced platelet activation

Objectives:

To determine the effect of thrombectomy on platelet function in patients undergoing primary percutaneous coronary intervention (PPCI) for ST segment elevation myocardial infarction (STEMI).

Methods:

This retrospective study included 413 consecutive STEMI patients who underwent PPCI between March 2012 and September 2013 at Kartal Kosuyolu High Specialty Education and Research Hospital, Istanbul, Turkey that were assigned to the thrombus aspiration (TA) group or the non-TA group. Platelet count and mean platelet volume (MPV) were obtained at baseline and 24 hours (h), 48 h, and 72 h post PPCI.

Results:

Baseline MPV was similar in both groups, whereas the baseline platelet count was higher in the TA group (p=0.42 and p=0.002). The platelet count was higher in the TA group 24 h post PPCI (p=0.02), but was similar in both groups 48 h and 72 h post PPCI (p=0.18 and p=0.07). The MPV 48 h and 72 h post PPCI was higher in the non-TA group than in the TA group (8.4 ± 1.3 fL versus 8.7 ± 1.6 fL [p=0.04] and 8.5 ± 1.1 fL versus 8.9 ± 1.5 fL [p=0.04]).

Conclusion:

Thrombectomy reduced platelet activity via removal of thrombi from the coronary arteries in patients undergoing PPCI for STEMI.

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.

MRI monitoring of function, perfusion and viability in microembolized moderately ischemic myocardium

Assessment of microembolization after coronary interventions is clinically challenging, thus we longitudinally investigated microemboli effects on moderately ischemic myocardium using MRI and histopathology. Twenty-four pigs (8/group) were divided into: group I (no intervention), group II (45 min LAD occlusion) and group III (45 min LAD occlusion with microembolization). Cine, perfusion and delayed contrast enhanced MRI (DE-MRI), using 1.5T MRI, were used for assessment at 3 days and 5 weeks. Triphenyltetrazolium-chloride (TTC) and Masson-trichrome were used as gold standard references for macro and microscopic quantification of myocardial infarction (MI). Cine MRI showed differential increase in end systolic volume (1.3 ± 0.08 ml/kg group II and 1.6 ± 0.1 ml/kg group III) and decrease in ejection fraction (45 ± 2 and 36 ± 2%, respectively) compared with controls at 3 days (2.1 ± 0.1 ml ESV and 50 ± 1% EF, P < 0.05). At 5 weeks group III, but not II, showed persistent perfusion deficits, wall thinning in the LAD territory and compensatory hypertrophy in remote myocardium. DE-MRI MI at 3 days was significantly smaller in group II (3.3 ± 2.2 g) than III (9.8 ± 0.6 g), at 5 weeks, MI were smaller by 60% (1.3 ± 0.9 g) and 22% (7.7 ± 0.5 g), respectively. TTC MI was similar to DE-MRI in group II (1.6 ± 1.0 g) and III (9.2 ± 1.6 g), but not microscopy (2.8 ± 0.4 and 10.5 ± 1.5 g, respectively). The effects of moderate ischemia with and without microembolization on myocardium could be differentiated using multiple MRI sequences. MRI demonstrated that microemboli in moderately ischemic myocardium, but not solely ischemia, prolonged ventricular dysfunction, created perfusion deficits, poor infarct resorption and enhanced compensatory hypertrophy, while moderate ischemia alone caused minor LV changes.