Successful CTO reduces local and remote residual ischemia

Courtesy of Dr. Carlos Fava.

The presence of Chronic Total Occlusion (CTO) is about 30%, with an ischemic threshold between 10% and 12.5% to justify rechannelization. Using the new devices, the new guidelines and with more experience operators, these procedures are successful in 10% to 30% of cases.

More often than not these patients are not treated because physicians will not see the benefit of treating this condition. Indeed, how we should treat these patients remains under debate.

The present prospective study included 69 patients undergoing successful CTO percutaneous coronary intervention (PCI). Patients received pre-procedural treatment and, after 12 weeks, a gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR). In addition, they received a positron emission tomography (PET) to assess absolute myocardial blood flow (MBF) with and without stress, and systolic function recovery.

Mean age was 63 (mostly men); BMI was 27.5 km/m²; HTA 34 patients; DLP 28; DBT 11; DLP 28; TBQ 22. Clinical presentation was: chronic stable angina 41, dyspnea 16 and silent ischemia 12.

Also read: “Successful PCI in older patients with chronic total occlusions reduces mortality”.

59 patients received CTO PCI exclusively and the remaining 10 PCI was associated to another vessel (it was not a case of CTO).

In the positron emission tomography after PCI, researchers observed an increase, mostly compared to baseline, in local and remote values of stress MBF (1.22±0.36 to 2.40±0.90 mL.min^-1.g^-1 p<0.001 and 2.58±0.68 to 2.77±0.77 mL.min-1.g-1 p=0.01).

MBF ratio between CTO and remote area increased between baseline and 12 weeks (0.49±0.13 vs. 0.87±0.24 p<0.001), and there was a reduction in defect CTO size after procedure (5.12±1.69 to 1.91±1.75 p<0.01).

Also read: “Is the transradial approach useful in chronic total occlusions?”

There was a significant increase in ejection fraction at follow up (46.4±11 vs. 47.5±11.4 p=0.01).

Conclusion

Most patients that had chronic total occlusion with ischemia and documented viability show significant improvement of stress MBF and reduced ischemia after successful PCI with minimal effect on ejection fraction.

Commentary

This analysis of successful OCT PCI in stable patients saw improved perfusion with minimal improvement in ventricular function.

It is difficult to analyze whether hard events such as mortality or AMI were reduced, since these are stable patients. We need several years of follow up to be able to see the actual benefit, given there might be several contradicting factors. 

What matters is knowing whether we will improve their quality of life. If we manage to reduce the need of drug treatment and que number of hospitalizations, we will reduce healthcare costs as well. 

Courtesy of Dr. Carlos Fava.

Original Title:Effect of successful percutaneous coronary intervention of chronic total occlusion on myocardial perfusion and left ventricular function.

Reference: Wijnand J. Stuijfzand et al. EuroIntervention 2017;13:345-354.

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