Statin therapy and myocardial no-reflow

Coronary vessel diameters during and after primary percutaneous coronary artery intervention

BACKGROUND

Primary percutaneous coronary intervention (P-PCI) is the gold standard treatment for acute coronary syndromes. Plasma levels of catecholamines and other vasopressors are elevated during acute myocardial infarction (AMI) and coronary vasoconstriction is frequent. We aimed to compare the reference vessel diameter (RVD) of the infarct-related artery (IRA) during primary PCI and after an average of 3 days.

METHODS

Coronary angiography (CAG) was performed on 58 patients with acute ST-segment elevation myocardial infarction (STEMI) and TIMI 3 flow after P-PCI (43 men, 15 women; mean age, 55.5 ± 10 years). TIMI 3 flow was achieved either by simple balloon dilatation and/or thrombus aspiration. Lesion length, RVD, minimal lumen diameter (MLD), mean vessel diameter (meanD), and area of stenosis were compared during P-PCI and follow-up CAG.

RESULTS

RVD, MLD, and meanD values were significantly higher during the follow-up CAG than after P-PCI (RVD 2.7 ± 0.7 mm vs. 2.9 ± 0.7 mm, p = 0.001; MLD 1.5 ± 0.5 mm vs. 1.7 ± 0.4 mm, p = 0.002; meanD 2.2 ± 0.5 mm vs. 2.4 ± 0.5 mm, p = 0.001). Area of stenosis values were significantly lower during the follow-up CAG than after primary PCI (69.5 ± 16.5 % vs. 62.1 ± 15 %, p = 0.001). Lesion lengths were not statistically significant during the follow-up CAG and primary PCI (lesion length 24.0 ± 10.8 mm vs. 22.1 ± 8.8 mm, p > 0.05).

CONCLUSION

This study showed that RVD was higher at the follow-up CAG a few days after AMI in patients who had TIMI 3 flow after P-PCI with simple balloon dilatation and/or thrombus aspiration. A delay of a few days for stent implantation in P-PCI allows for larger-diameter stent use and may help to reduce stent thrombosis and restenosis rates.

Natural product nitric oxide chemistry: new activity of old medicines

The use of complementary and alternative medicine (CAM) as a therapy and preventative care measure for cardiovascular diseases (CVD) may prove to be beneficial when used in conjunction with or in place of conventional medicine. However, the lack of understanding of a mechanism of action of many CAMs limits their use and acceptance in western medicine. We have recently recognized and characterized specific nitric oxide (NO) activity of select alternative and herbal medicines that may account for many of their reported health benefits. The ability of certain CAM to restore NO homeostasis both through enhancing endothelial production of NO and by providing a system for reducing nitrate and nitrite to NO as a compensatory pathway for repleting NO bioavailability may prove to be a safe and cost-effective strategy for combating CVD. We will review the current state of science behind NO activity of herbal medicines and their effects on CVD.

Effect of delayed vs immediate stent implantation on myocardial perfusion and cardiac function in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous intervention with thrombus aspiration

BACKGROUND

Optimizing microcirculation in STEMI patients with thrombus-containing lesion undergoing percutaneous coronary intervention (PCI) remains challenging. Our objective was to compare the effects on myocardial perfusion and cardiac function of delayed vs immediate stent implantation after thrombus aspiration in STEMI patients undergoing PCI.

METHODS

Eighty-seven STEMI patients with thrombus-containing lesion undergoing PCI were enrolled. After thrombus aspiration was performed, subjects were divided into 2 groups according to residual thrombus score (TS): immediate stent implantation (ISI) group (n = 47, residual TS < 2; stenting was performed immediately), and delayed stent implantation (DSI) group (n = 40, residual TS ≥ 2; stenting was performed 7 days later). Corrected thrombolysis in myocardial infarction frame count and myocardial blush grade were analyzed immediately after PCI. The wall motion score index was assessed on admission and at 6-month follow-up.

RESULTS

At the end of the PCI procedure, the corrected thrombolysis in myocardial infarction frame count was significantly shorter and the myocardial blush grade 3 was more frequent in the DSI group than in the ISI group. Compared with the ISI group, the DSI group had a lower incidence of thrombus-related angiographic events, including distal embolization and no reflow. A significantly greater improvement in wall motion score index from baseline to 6-month follow-up was observed in the DSI group compared with the ISI group.

CONCLUSIONS

In STEMI patients presenting with thrombus containing lesion undergoing PCI, delayed stent implantation after thrombus aspiration leads to better myocardial perfusion and cardiac functional recovery in comparison with immediate stent implantation.

Emerging role of nitrite in myocardial protection

Nitrite has long been considered an inert oxidative metabolite of nitric oxide (NO). However, recent experimental findings strongly suggest that nitrite is a critical storage form of NO that is converted back into NO during ischemic or hypoxic events as well as under physiological conditions. Thus, the conversion of nitrite into NO during cellular stress may be an evolutionarily conserved and redundant means for NO generation at a time when endothelial nitric oxide synthase is non-functional. As a result of the recent revelation that the nitrite anion serves an important biological function a large number of studies have been performed to characterize both the physiological actions and therapeutic potential of nitrite under diverse conditions. While the earliest experiments characterized the vasodilatory effects of nitrite in both animal models and humans, more recent research efforts have focused on the potential benefits of nitrite in a number of pathological states. Nitrite therapy has now been studied in numerous animal models and has proven to be an effective means to ameliorate myocardial ischemia-reperfusion (I/R) injury. This review will focus on recent experimental findings related to the cytoprotective actions of nitrite therapy in the setting of myocardial I/R injury.

Myocardial protection by nitrite

Nitrite has long been considered to be an inert oxidative metabolite of nitric oxide (NO). Recent work, however, has demonstrated that nitrite represents an important tissue storage form of NO that can be reduced to NO during ischaemic or hypoxic events. This exciting series of discoveries has created an entirely new field of research that involves the investigation of the molecular, biochemical, and physiological activities of nitrite under a variety of physiological and pathophysiological states. This has also led to a re-evaluation of the role that nitrite plays in health and disease. As a result there has been an interest in the use of nitrite as a therapeutic strategy for the treatment of acute myocardial infarction. Nitrite therapy has now been studied in several animal models and has proven to be an effective means to reduce myocardial ischaemia-reperfusion injury. This review article will provide a brief summary of the key findings that have led to the re-evaluation of nitrite and highlight the evidence supporting the cardioprotective actions of nitrite and also highlight the potential clinical application of nitrite therapy to cardiovascular diseases.

Inhibition of N-ethylmaleimide-sensitive factor protects against myocardial ischemia/reperfusion injury

Exocytosis of endothelial granules promotes thrombosis and inflammation and may contribute to the pathophysiology of early reperfusion injury following myocardial ischemia. TAT-NSF700 is a novel peptide that reduces endothelial exocytosis by inhibiting the ATPase activity and disassembly activity of N-ethylmaleimide-sensitive factor (NSF), a critical component of the exocytic machinery. We hypothesized that TAT-NSF700 would limit myocardial injury in an in vivo murine model of myocardial ischemia/reperfusion injury. Mice were subjected to 30 minutes of ischemia followed by 24 hours of reperfusion. TAT-NSF700 or the scrambled control peptide TAT-NSF700scr was administered intravenously 20 minutes before the onset of ischemia. Myocardial ischemia/reperfusion caused endothelial exocytosis, myocardial infarction, and left ventricular dysfunction. However, TAT-NSF700 decreased von Willebrand factor levels after myocardial ischemia/reperfusion, attenuated myocardial infarct size by 47%, and preserved left ventricular structure and function. These data suggest that drugs targeting endothelial exocytosis may be useful in the treatment of myocardial injury following ischemia/reperfusion.