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Published on: April 13, 2015
Coronary Flow Variations Following Percutaneous Coronary Intervention Affect Diastolic Nonhyperemic Pressure Ratios
Muhammad Aetesam-Ur-Rahman1, Tian X Zhao1, Kitty Paques1
1Department of Interventional Cardiology Royal Papworth Hospital Cambridge United Kingdom.
Insights
Post-percutaneous coronary intervention (PCI) whole cardiac cycle nonhyperemic pressure ratios (NHPRs) show better stability and reproducibility than diastolic NHPRs. This finding is crucial for accurately assessing procedural success after PCI.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Hemodynamics
Background:
- Post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) ≥0.90 indicates procedural success.
- The stability and reproducibility of nonhyperemic pressure ratios (NHPRs) after PCI are not well understood.
- Transient submaximal hyperemia post-PCI may impact the precision of NHPRs.
Purpose of the Study:
- To assess the stability and reproducibility of various NHPRs immediately after PCI and during a recovery period.
- To evaluate the impact of transient hyperemia on post-PCI hemodynamic measurements.
Main Methods:
- Fifty-seven patients underwent hemodynamic assessment immediately post-PCI and at 10, 20, and 30 minutes, with repeat assessment at 3 months.
- Offline analysis derived pressure indexes (e.g., Pd/Pa, instantaneous wave-free ratio, resting full cycle ratio, FFR) and microcirculatory resistances.
- Thermodilution time and basal microcirculatory resistance were measured to assess hyperemia.
Main Results:
- Transient submaximal hyperemia was observed post-PCI, indicated by increased thermodilution time and basal microcirculatory resistance at 30 minutes.
- No significant differences were found in resting whole cycle pressure ratios (Pd/Pa, resting full cycle ratio) and diastolic pressure ratios (diastolic pressure ratio, mathematically derived instantaneous wave-free ratio) between time points.
- Whole cardiac cycle NHPRs demonstrated superior stability post-PCI compared to diastolic NHPRs, with 1 in 5 diastolic NHPRs crossing the clinical decision threshold upon repetition.
Conclusions:
- Whole cardiac cycle NHPRs exhibit better reproducibility and clinical precision following PCI than diastolic NHPRs.
- The improved stability of whole cycle NHPRs may be attributed to reduced perturbation from diastolic reactive hyperemia and left ventricular stunning.
- These findings support the use of whole cardiac cycle NHPRs for more reliable assessment of PCI procedural success.
Abstract:
Background Post-percutaneous coronary intervention (PCI) fractional flow reserve ≥0.90 is an accepted marker of procedural success, and a cutoff of ≥0.95 has recently been proposed for post-PCI instantaneous wave-free ratio. However, stability of nonhyperemic pressure ratios (NHPRs) post-PCI is not well characterized, and transient reactive submaximal hyperemia post-PCI may affect their precision. We performed this study to assess stability and reproducibility of NHPRs post-PCI. Methods and Results Fifty-seven patients (age, 63.77±10.67 years; men, 71%) underwent hemodynamic assessment immediately post-PCI and then after a recovery period of 10, 20, and 30 minutes and repeated at 3 months. Manual offline analysis was performed to derive resting and hyperemic pressure indexes (Pd/Pa resting pressure gradient, mathematically derived instantaneous wave-free ratio, resting full cycle ratio, and fractional flow reserve) and microcirculatory resistances (basal microvascular resistance and index of microvascular resistance). Transient submaximal hyperemia occurring post-PCI was demonstrated by longer thermodilution time at 30 minutes compared with immediately post-PCI; mean difference of thermodilution time was 0.17 seconds (95% CI, 0.07-0.26 seconds; P=0.04). Basal microcirculatory resistance was also higher at 30 minutes than immediately post-PCI; mean difference of basal microvascular resistance was 10.89 mm Hg.s (95% CI, 2.25-19.52 mm Hg.s; P=0.04). Despite this, group analysis confirmed no significant differences in the values of resting whole cycle pressure ratios (Pd/Pa and resting full cycle ratio) as well as diastolic pressure ratios (diastolic pressure ratio and mathematically derived instantaneous wave-free ratio). Whole cardiac cycle NHPRs demonstrated the best overall stability post-PCI, and 1 in 5 repeated diastolic NHPRs crossed the clinical decision threshold. Conclusions Whole cycle NHPRs demonstrate better reproducibility and clinical precision post-PCI than diastolic NHPRs, possibly because of less perturbation from predominantly diastolic reactive hyperemia and left ventricular stunning. Registration URL: https://clinicaltrials.gov/ct2/show/NCT03502083; Unique identifier: NCT03502083 and URL: https://clinicaltrials.gov/ct2/show/NCT03076476; Unique identifier: NCT03076476.
