Physiology in PCI: It is Not That Very simple

Coronary physiology flopped in several scientific tests for pinpointing whether to defer invasive methods and in optimizing percutaneous coronary intervention (PCI), scientists reported, suggesting there’s much more to study.

“We need to fork out much more notice to the precise physiology of what we are measuring and what it usually means,” said K. Lance Gould, MD, of McGovern Health care Faculty at UTHealth in Houston.

1 team identified that schedule use of computed tomography-derived fractional circulation reserve (FFR_CT) did not shave health care fees in people with stable upper body soreness, whilst yet another described that operators having more methods through stenting did not realize far more best FFRs right after PCI.

Last but not least, an observational research confirmed that coronary movement reserve (CFR) could not trump FFR at existing thresholds in choosing which patients may perhaps defer revascularization.

The three scientific tests have been introduced for the duration of the exact same late-breaking demo session at this year’s TCT Hook up, held virtually by the Cardiovascular Exploration Basis.

FORECAST

Resource utilization was about the exact same no matter if chest soreness clinics in the U.K. adopted regimen FFR_CT as a frontline check or continued standard treatment, according to a randomized trial.

Overall professional medical expenditures — counting the charge of non-invasive cardiac tests, invasive coronary angiography (ICA), revascularization, hospitalization for cardiac functions, cardiac medications, and outpatient attendances — averaged £1,605.50 at 9 months for people randomly assigned to frontline FFR_CT screening vs £1,491.46 in controls (or median £600 vs £670, P=.962).

There was no variation in between groups in medical results nor high quality-of-existence position at that stage, in accordance to Nick Curzen, PhD, of the College of Southampton in England.

Hence, the final results contradict U.K. recommendations, which recommend coronary CT angiography and HeartFlow FFR_CT together as a expense-conserving technique primarily based on National Institute for Overall health and Treatment Excellence projections.

FFR_CT is FFR derived from coronary CT angiography, therefore providing anatomical and physiological data, and is considered to be a protected way to decide on individuals for subsequent invasive testing and remedy of angina.

“The true crux of FFR_CT is can it preserve dollars? We can, but not by doing it so freely,” Curzen concluded at a press convention.

For the FORECAST examine, investigators experienced 1,400 people today presenting to 11 chest soreness clinics in the U.K. randomized to the take a look at team acquiring program FFR_CT or typical treatment. Median age was all over 60 many years, and just about 50 {462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of the individuals ended up males.

Coronary CT angiography use was 96{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} in the examination team and 66{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} in the reference team. Total ICA exams were being 14{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} lessen in the take a look at group (P=.02), which also experienced 22{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} less people undergoing ICAs (P=.01).

On nearer inspection, the check group experienced coronary CT angiography alone in 64.9{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of cases, as most individuals had no lesions with >40{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} stenosis. Another 31.5{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} actually went on to get FFR_CT evaluation. None underwent stress echocardiography, perfusion scanning, pressure MRI, exercise ECG, or ICA screening.

In contrast, the reference group experienced patients stop at coronary CT angiography in 61.4{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of circumstances. Dozens obtained the other non-invasive and invasive assessments.

Nevertheless, ICAs and revascularizations were not minimized more than enough by the FFR_CT strategy to make it expense-dominant, Curzen stated.

Concentrate on-FFR

Operators adhering to a physiology-guided incremental optimization technique did not see an enhancement in the quantity of individuals coming out of PCI with ideal FFRs, a person center described.

Soon after angiographically thriving PCI, FFR was ≥0.90 in 32{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of individuals, .81-.89 in 39{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}, and ≤0.80 in 29{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}, according to Damien Collison, MD, of Golden Jubilee Nationwide Healthcare facility and College of Glasgow in Scotland.

Sufferers randomized to additional intervention to strengthen FFR wound up with 38.1{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} reaching FFR ≥0.90, which was statistically no much better than the 28.1{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of controls (P=.099). Even so, the proportion of patients with a last FFR ≤0.80 was lessen in the intervention group (18.6{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} vs 29.8{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}, P=.045).

Collison mentioned that it is exceptional for operators to evaluate PCI success using FFR.

“It can be shocking to see so number of sufferers who meet up with the conditions for optimal physiology at the finish of the technique,” mentioned the moderator of the press conference, Roxana Mehran, MD, of Mount Sinai University of Medication in New York City.

Chad Rammohan, MD, of Mountain Perspective Centre in California, agreed: It really is “a very little sobering” to comprehend that 30{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of clients at a excellent center are continue to ischemic at the stop of PCI, with an FFR under .80. The study moves the discipline toward optimization and applying imaging to make PCI final results more durable, he explained.

The tiny Goal-FFR trial was carried out at a solitary middle. Included were being 260 people today who experienced angiographically productive PCI right before randomization to physiology-guided PCI optimization or usual treatment.

Operators adhering to the intervention algorithm done further more article-dilation, intracoronary imaging, supplemental stenting depending on coronary physiology final results, and hyperemic pullback evaluation.

Even more optimization was specific in 46{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} of the intervention group. Two-thirds of these individuals have been considered suitable for further article-dilation and/or stenting.

In these 40 patients who truly received PCI optimization, suggest FFR greater from .76 to .82 (P<0.00) and mean coronary flow reserve was boosted from 3.0 to 4.0 (P=0.02).

Mehran cautioned that perfect is the enemy of the good, as performing extra procedures in PCI may run the risk of cardiac perforation.

DEFINE-FLOW

FFR-positive patients did not have good clinical outcomes if they had PCI deferred due to a negative CFR result, according to an observational study of combined CFR and FFR assessment.

A treatment algorithm for 455 people with stable coronary lesions dictated that only those who had abnormally low FFR (0.8 or below) and CFR (below 2) would receive PCI, with all others receiving initial medical therapy, Gould reported.

Resulting major adverse cardiovascular events (MACE) rates, counting all-cause death, myocardial infarction, and revascularization, revealed that outcomes were not equal among patients at 2 years:

• Concordant negative (FFR-/CFR-): 5.8{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}

• Discordant (FFR+/CFR-): 10.8{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}

• Discordant (FFR-/CFR+): 12.4{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}

• Concordant positive (FFR+/CFR+): 14.4{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694}

The 10.8{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} MACE rate of the FFR+/CFR- group was not as good as the 5.8{462f6552b0f4ea65b6298fc393df649b8e85fbb197b4c3174346026351fdf694} rate for FFR-/CFR- (P=0.065 for non-inferiority), Gould reported.

“Trust the FFR” was Rammohan’s take-away in discussing the DEFINE-FLOW study at a press conference.

Gould suggested the possibility that reduced FFR and CFR together may still incur additive risk, just at lower thresholds than the ones used for this study. Large randomized trials are needed with thresholds that may actually result in a decrease in morbidity and mortality, he said.

CFR is the ratio between resting and maximal possible coronary blood flow. This measure fails to distinguish flow-limiting stenosis from diffuse or microvascular disease, Gould noted.

Mechanisms controlling coronary blood flow are complex, with physiology differing between the subepicardium and the subendocardium. For instance, high flow may be good for the former but not the latter, he said.

Last Updated October 16, 2020