Urate production by human heart

Xanthine oxidoreductase has been demonstrated in the heart of various species. However, its presence in human heart is still debated. In the literature, high to undetectable levels have been reported. We studied the arterial-venous urate difference across the heart of patients undergoing both routine cardiac catheterization and percutaneous transluminal coronary angioplasty. Urate is the end product of the reaction catalysed by xanthine oxidoreductase. In 10 patients, studied before angioplasty, the plasma urate level in the great cardiac vein exceeded the arterial one by 26 +/- 10 nmol/ml (P = 0.028). In a further 13 patients, urate production was maximal immediately after the last of four consecutive occlusions (23 +/- 8 nmol/ml, P = 0.018) and concomitant with increased coronary sinus hypoxanthine levels. We conclude that xanthine oxidoreductase is probably present in the heart of patients, suffering from ischemic heart disease, and responsible for the increase in urate production during transient myocardial ischemia.

Myocardial protection by intravenous diltiazem during angioplasty of single-vessel coronary artery disease

The possible cardioprotective effect of diltiazem during ischemia caused by percutaneous transluminal coronary angioplasty was tested. Electrocardiograms and myocardial lactate, hypoxanthine and urate production were determined in 26 patients with a stenosis in the left anterior descending artery without angiographically demonstrable collaterals. Measurements took place before angioplasty, after each of 4 occlusions and 15 minutes after the last balloon inflation. Patients were randomly given placebo or DL-diltiazem (0.4 mg/kg as a bolus intravenously, followed by an infusion of 15 mg/hr). During angioplasty the ST-segment elevation for the anterior wall leads V2, V4 and V6, and the intracoronary lead was similar for both groups, as was lactate release. Diltiazem significantly reduced cardiac hypoxanthine release immediately after angioplasty from 63 to 88% (p less than 0.05). The drug diminished urate production after the last dilatation by 82% (p less than 0.05). In conclusion, intravenous infusion of diltiazem reduced cardiac adenosine triphosphate breakdown during angioplasty as shown by diminished hypoxanthine and urate production. In contrast, diltiazem was unable to attenuate ST-segment elevation and lactate release.

Two-year results from Onyx ONE clear in patients with high bleeding risk on one-month DAPT with and without intracoronary imaging

BACKGROUND

Patients with high bleeding risk (HBR) are often treated with abbreviated dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) to reduce bleeding risk, however this strategy is associated with an increase in ischemic events, especially if the acute PCI result is suboptimal. We compared clinical outcomes among patients with HBR treated with 1-month DAPT who underwent intravascular ultrasound (IVUS)- or optical coherence tomography (OCT)-guided PCI versus those who underwent angiography-guided PCI without intravascular imaging.

METHODS

The Onyx ONE Clear study includes patients with HBR from the Onyx ONE US/Japan and Onyx ONE randomized studies who were treated with the Resolute Onyx zotarolimus-eluting stent. The primary endpoint was the composite of cardiac death (CD) or myocardial infarction (MI) between 1 month and 2 years after PCI. Propensity-score adjustments and matching were performed for differences in baseline and procedural characteristics between groups.

RESULTS

Among the 1507 patients in Onyx ONE Clear, 271 (18.0 %) had IVUS or OCT used during PCI (Imaging-guided group) and 1236 (82.0 %) underwent Angiography-guided PCI (Angio-guided group). Imaging-guided patients were less likely to present with atrial fibrillation, acute coronary syndrome, and left ventricle ejection fraction ≤35 %. Conversely, Imaging-guided patients were more likely to have complex (ACC/AHA type B2/C), longer, and heavily calcified lesions. Between 1 month and 2 years, the composite rate of CD or MI was similar between Imaging-guided and Angio-guided patients (9.9 % vs. 12.4 %, P = 0.33). There was also no difference between groups after adjustment; (P = 0.56). However, CD was significantly lower among Imaging-guided patients (2.7 % vs. 6.1 %, P = 0.048). There were no between-group differences in MI or stent thrombosis. Propensity score matching results were similar.

CONCLUSION

Despite higher lesion complexity, using intravascular imaging guidance for PCI between 1-month and 2-years follow-up had comparable outcomes with angiographic guidance alone in patients with HBR treated with 1-month DAPT. (ClinicalTrials.gov: Identifier: NCT03647475 and NCT03344653).

NON-STANDARD ABBREVIATIONS AND ACRONYMS

BARC: Bleeding Academic Research Consortium; DAPT: dual antiplatelet therapy; DES: drug-eluting stent; HBR: high bleeding risk; IVUS: intravascular ultrasound; OCT: optical coherence tomography; SAPT: single antiplatelet therapy.