Low Coronary Microcirculatory Resistance Associated With Profound Hypotension During Intravenous Adenosine Infusion

• Original Article

Low Coronary Microcirculatory Resistance Associated With Profound Hypotension During Intravenous Adenosine Infusion

Implications for the Functional Assessment of Coronary Stenoses

1. Mauro Echavarría-Pinto, MD, 
2. Nieves Gonzalo, MD, PhD, 
3. Borja Ibañez, MD, PhD, 
4. Ricardo Petraco, MD, 
5. Pilar Jimenez-Quevedo, MD, PhD,
6. Sayan Sen, MBBS, 
7. Sukkinder Nijjer, MBBS, 
8. Jason Tarkin, MD,
9. Fernando Alfonso, MD, PhD, 
10. Ivan J. Núñez-Gil, MD, PhD,
11. Camino Bañuelos, MD, 
12. Alicia Quirós, PhD, 
13. Antonio Fernández-Ortiz, MD, PhD, 
14. Carlos Macaya, MD, PhD, 
15. Bon-Kwon Koo, MD, PhD,
16. Justin Davies, PhD, MRCP and 
17. Javier Escaned, MD, PhD

+Author Affiliations

1. From the Cardiovascular Institute, Hospital Clínico San Carlos and Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain (M.E.-P., B.I., A.Q., A.F.-O., J.E.); Cardiovascular Institute, Hospital Clínico San Carlos, Madrid, Spain (N.G., P.J.-Q., F.A., I.J.N.-G., C.B., C.M.); International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London and Imperial College Healthcare NHS Trust, London, United Kingdom (R.P., S.S., S.N., J.T., J.D.); and Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea (B.K.K.).

1. Correspondence to Javier Escaned, MD, PhD, Instituto Cardiovascular, Hospital Clínico San Carlos and Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28040 Madrid, Spain. E-mail escaned@secardiologia.es

Abstract

Background—Intravenous adenosine infusion produces coronary and systemic vasodilatation, generally leading to systemic hypotension. However, adenosine-induced hypotension during stable hyperemia is heterogeneous, and its relevance to coronary stenoses assessment with fractional flow reserve (FFR) remains largely unknown.

Methods and Results—FFR, coronary flow reserve, and index of microcirculatory resistance were measured in 93 stenosed arteries (79 patients). Clinical and intracoronary measurements were analyzed among tertiles of the percentage degree of adenosine-induced hypotension, defined as follows: %ΔP_a=–[100–(hyperemic aortic pressure×100/baseline aortic pressure)]. Overall, %ΔP_a was –13.6±12.0%. Body mass index was associated with %ΔP_a (r=0.258; P=0.025) and obesity, an independent predictor of profound adenosine-induced hypotension (tertile 3 of %ΔP_a; odds ratio, 3.95 [95% confidence interval, 1.48–10.54]; P=0.006). %ΔP_a was associated with index of microcirculatory resistance (ρ=0.311; P=0.002), coronary flow reserve (r=–0.246; P=0.017), and marginally with FFR (r=0.203;P=0.051). However, index of microcirculatory resistance (β=0.003; P<0.001) and not %ΔP_a (β=–0.001; P=0.564) was a predictor of FFR. Compared with tertiles 1 and 2 of %ΔP_a (n=62 [66.6%]), stenoses assessed during profound adenosine-induced hypotension (n=31 [33.3%]) had lower index of microcirculatory resistance (12.4 [8.6–22.7] versus 20 [15.8–35.5]; P=0.001) and FFR values (0.77±0.13 versus 0.83±0.12; P=0.021), as well as a nonsignificant increase in coronary flow reserve (2.5±1.1 versus 2.2±0.87; P=0.170).

Conclusions—The modification of systemic blood pressure during intravenous adenosine infusion is related to hyperemic microcirculatory resistance in the heart. Profound adenosine-induced hypotension is associated with obesity, lower coronary microcirculatory resistance, and lower FFR values.

Key Words:

• adenosine
• coronary disease
• physiology

• Received June 3, 2013.
• Accepted December 9, 2013.

• © 2014 American Heart Association, Inc.