Impact of intracoronary contrast injection pressure on reperfusion during primary percutaneous coronary intervention in acute ST-segment elevation myocardial infarction: A prospective randomized pilot study

Background

Distal embolization of plaque and thrombotic debris in the infarct-related artery (IRA) may lead to microvascular obstruction resulting in impaired myocardial reperfusion.

The aim of the study was to assess the impact of contrast injection pressure in IRA, during primary percutaneous coronary intervention (PCI), on myocardial reperfusion in patients with acute ST-segment elevation myocardial infarction (STEMI).

Methods

This prospective, randomized, open label, pilot trial evaluated acute STEMI patients who underwent primary PCI, with blinded evaluation of end points. Patients were assigned to higher injection pressure group A (550 pound/inch²) or lower injection pressure group B (200 pound/inch²). Primary endpoint was the postprocedural incidence of restored myocardial perfusion defined as myocardial blush grade (MBG) 3.

Results

Study included 100 consecutive acute STEMI patients, with median age of 63 (56–72) years (77% men) who were randomized to higher and lower injection pressure group. Baseline demographic, clinical and angiographic characteristics did not differ significantly between the groups. There were no significant differences between the study groups regarding difference in achieved MBG 3 (33 vs 36 patients, p = 0.247) nor regarding the ST-segment deviation score neither immediately after (3 vs 4 mm, p > 0.3) nor 24 h after primary PCI (2 vs 3 mm, p > 0.3).

Conclusion

There was no impact of lower intracoronary contrast injection pressure in comparison to higher injection pressure, during primary PCI in patients with acute STEMI, on myocardial reperfusion as assessed by MBG or ST segment changes in the ECG.

The study was registered at registry ClinicalTrials.gov with the registration number: NCT03445364, on February 26th 2018.

A mechanism for stroke complicating thrombus aspiration

We propose a mechanism of how stroke may be caused by thrombus aspiration during primary percutaneous coronary intervention (PPCI), and how it may be technique-dependent. Two recent meta-analyses report increased risk of stroke in patients undergoing routine thrombus aspiration during STEMI and the value of this technique has been controversial. The mechanism of stroke has not been fully explained. This case demonstrates 2 mechanisms by which aspiration might cause thrombus embolization. We recommend that if thrombus aspiration is performed during PPCI for STEMI, it should be done selectively and carefully. It is prudent to make sure the guide catheter tip is not free in the aorta when the aspiration catheter is withdrawn, to maintain suction on the aspiration catheter as it is withdrawn (particularly if the aspiration port seems to be obstructed), and to aspirate the guide catheter after the aspiration catheter is removed to capture any fragments of thrombus that remain in the guide catheter. © 2016 Wiley Periodicals, Inc.

Manual aspiration thrombectomy devices use in coronary interventions in 2016

Percutaneous coronary intervention is a highly effective therapy of acute myocardial infarction. Restoration of microcirculation is however often sub-optimal with negative impact on patient outcome. Distal thrombus embolization may contribute to this issue. Simple manual aspiration thrombectomy catheters were developed with aim of thrombus extraction. There are several of these devices with very similar design. Thrombotic or atheromatous tissue is successfully retrieved in over 70% of patients. The initial results of small, often single center studies have provided encouraging results. Unfortunately, three further studies clearly demonstrated lack of any clinical benefit and routine use of manual aspiration thrombectomy cannot be recommended. Small but statistically significant increase in stroke rate is the major safety issue. Selective use in patients with large thrombus burden or suboptimal flow or perfusion is likely to continue and needs to be scientifically studied.