Abstract
Introduction
The aim of this study was to investigate the efficacy and safety of intracoronary (IC) sodium nitroprusside infusion in comparison to IC adenosine for fractional flow reserve (FFR) measurement in moderately diseased coronary artery lesions for functional assessment.
Methods
During a nine month period, a consecutive of 98 patients with suspected or known coronary artery disease with moderate stenosis found during angiography (40% to 70% stenosis), were enrolled in this study. Hyperemia was induced by bolus doses of IC adenosine followed by sodium nitroprusside for FFR measurement.
Results
Both IC adenosine and IC sodium nitroprusside induced similar and significant reduction in FFR. There was no statistically difference in FFR values between adenosine vs sodium nitroprusside infusions (mean FFR 84.3 ± 6.3 vs 85.7 ± 6.2, p = 0.1) respectively. Furthermore, comparing different FFR cut-off points between the groups (FFR < 0.75, 0.75–0.8 and > 0.8) showed no significant differences ( p value = 0.7).
Conclusion
An IC bolus of sodium nitroprusside (0.6 μg/kg) infusion induces a similar degree of hyperemia to IC bolus of 100–300 μg of adenosine. Therefore, IC sodium nitroprusside could be considered as an alternative drug to adenosine for FFR measurement with lower side effect profile.
Highlights
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Intracoronary (IC) sodium nitroprusside was compared with IC adenosine for FFR test.
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IC adenosine and IC sodium nitroprusside induced similar reduction in FFR.
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Different FFR cut-off points between the groups showed no significant differences.
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IC sodium nitroprusside could be considered as an alternative to adenosine for FFR.
1
Introduction
Fractional flow reserve (FFR) measurement is used to assess the hemodynamic significance of an intermediate coronary artery lesion . It represents the ratio of mean arterial pressure after a stenotic lesion to the pressure before the lesion after inducing maximal blood flow . Studies have shown that lesions with an FFR measurement of less than 0.75 or 0.8 are frequently associated with myocardial ischemia . In patients with coronary stenosis based on coronary angiography and an FFR of ≥ 0.8, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) showed no significant benefit in clinical outcome . For FFR measurement, pharmacologic stimuli are needed to induce coronary hyperemia. Intravenous (IV) adenosine infusion is currently considered the gold standard for FFR evaluation. However, the intracoronary (IC) or IV administration of adenosine may lead to undesirable side effects such as severe bradycardia, flushing, hypotension, gastrointestinal symptoms and bronchospasm. Sodium nitroprusside (NTP) represents a valuable alternative to the adenosine with lower side effect profile. Small studies have been promising. The purpose of this study was to compare the efficacy and safety of IC NTP with IC adenosine for fractional flow reserve (FFR) measurement in order to confirm previous small investigations and also to evaluate side effect profile of NTP in comparison to adenosine.
2
Patients and methods
During a nine month period, a consecutive of 98 patients with chronic stable angina who were found to have moderate coronary stenotic lesions during angiography (40% to 70% stenosis) were enrolled. Angiogram was performed for clinical indications. Patients with hemodynamic instability (SBP < 100) were excluded. Written informed consent was obtained from each patient before the procedure. The study was approved by institutional review board.
2.1
Catheterization procedure
After diagnostic angiography via femoral artery, patients with moderate coronary lesions were enrolled for FFR evaluation. Those patients who had history of previous acute coronary syndromes including myocardial infarction, congestive heart failure, previous percutaneous coronary intervention, and previous coronary artery bypass grafting, or who had sequential (more than one lesion in the target vessel) were excluded from the study. Intra-coronary (IC) bolus of adenosine (100 μg) was administered through a guide catheter and maximal hyperemia was measured via FFR. The lowest level of FFR was recorded as maximal hyperemic response. After 5 min, hyperemia was induced again by a 0.6 μg/kg bolus of IC NTP with repeat FFR measurement.
Patient’s symptoms (including angina-like sensation, dyspnea, or flushing), development of AV block or any other complications were carefully recorded. Mean FFR values as well as the number of patients with the cutoff point of different FFR values were compared between the adenosine and NTP treated obtained values.
2.2
Statistical analyses
Data are shown as means ± SD. Chi-square test was used for categorical variables and independent Student’s t- tests or ANOVA tests for continuous variables. Paired t test was used to compare changes in FFR values before and after IC infusion. Statistical analyses were performed with SPSS software for Windows (Statistical Product and Service Solutions, version 16.0, SSPS Inc., Chicago, IL, USA). A p value of less than 0.05 was considered significant.
2
Patients and methods
During a nine month period, a consecutive of 98 patients with chronic stable angina who were found to have moderate coronary stenotic lesions during angiography (40% to 70% stenosis) were enrolled. Angiogram was performed for clinical indications. Patients with hemodynamic instability (SBP < 100) were excluded. Written informed consent was obtained from each patient before the procedure. The study was approved by institutional review board.
2.1
Catheterization procedure
After diagnostic angiography via femoral artery, patients with moderate coronary lesions were enrolled for FFR evaluation. Those patients who had history of previous acute coronary syndromes including myocardial infarction, congestive heart failure, previous percutaneous coronary intervention, and previous coronary artery bypass grafting, or who had sequential (more than one lesion in the target vessel) were excluded from the study. Intra-coronary (IC) bolus of adenosine (100 μg) was administered through a guide catheter and maximal hyperemia was measured via FFR. The lowest level of FFR was recorded as maximal hyperemic response. After 5 min, hyperemia was induced again by a 0.6 μg/kg bolus of IC NTP with repeat FFR measurement.
Patient’s symptoms (including angina-like sensation, dyspnea, or flushing), development of AV block or any other complications were carefully recorded. Mean FFR values as well as the number of patients with the cutoff point of different FFR values were compared between the adenosine and NTP treated obtained values.
2.2
Statistical analyses
Data are shown as means ± SD. Chi-square test was used for categorical variables and independent Student’s t- tests or ANOVA tests for continuous variables. Paired t test was used to compare changes in FFR values before and after IC infusion. Statistical analyses were performed with SPSS software for Windows (Statistical Product and Service Solutions, version 16.0, SSPS Inc., Chicago, IL, USA). A p value of less than 0.05 was considered significant.
3
Results
Ninety-eight patients (66 men and 32 women) with moderate stenotic coronary lesions found during angiography were studied. The mean age was 62.3 ± 4.7 years. The demographic characteristics of patients can be seen in Table 1 . Vessels involved were as follows: left anterior descending in 43 patients (43.9%), left circumflex in 22 (22.5%), right coronary artery in 26 (26.5%) and obtuse marginal artery in 7 patients (7.1%) respectively. The average stenosis seen on angiography was 61% ± 6% which was measured by quantitative coronary angiography (QCA).
| ( n = 98) | |
|---|---|
| Age | 62.3 ± 4.7 |
| Sex (male/female) | (66/32) |
| Smoking | 43 |
| Diabetes | 48 |
| Hypertension | 36 |
| Dyslipidemia | 29 |
| Prevalence of involved coronary arteries | |
| Left anterior descending (LAD) | 43 (43.9%) |
| Right coronary artery (RCA) | 26 (22.5%) |
| Left circumflex artery (LCX) | 22 (26.5%) |
| Optus marginalis (OM) | 7 (7.1%) |
| Average lesion stenosis | 61 ± 6% |
| Average reference diameter of lesion | 2.9 mm (2.5–3.8) |
| Average lesion length | 16.2 mm (8–28) |
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