Effect of Spinal Cord Stimulation on Myocardial Flow Reserve in Patients with Refractory Angina Pectoris Antti Varis, Heikki Ukkonen, Antti Saraste, Tuija Vasankari, Satu Tunturi, Markku Taittonen, Pirkka Rautakorpi, Matti Luotolahti, Juhani Airaksinen, Juhani Knuuti Turku University Hospital, Department of Medicine, Anesthesiology, and Clinical Physiology, Nuclear Medicine and, University of Turku, Finland
Presenter Disclosure Information Antti Varis Effect of Spinal Cord Stimulation on Myocardial Flow Reserve in Patients with Refractory Angina Pectoris FINANCIAL DISCLOSURE: Unrestricted grant from St. Jude Medical, Inc. UNLABELED/UNAPPROVED USES DISCLOSURE: no
Background What is refractory angina pectoris?: Chronic condition caused by clinically established reversible myocardial ischemia in the presence of coronary artery disease, which cannot be adequately controlled by a combination of medical therapy, angioplasty or coronary bypass operations ESC Joint Study Group 2002 Epidural spinal cord stimulation (SCS) was first introduced as a treatment for refractory angina pectoris by Murphy et al in 1987
Background Anti-anginal effect of SCS has been proved by several randomized controlled trials Decreased need for short-acting-nitrates De Jongste 1994, Mannheimer 1998, Jessurun 1999, Eddicks 2007 Lower CCS class McNab 2006, Eddicks 2007 Improved health-related quality of life Ekre 2002, McNab 2006, De Jongste 1994, Hautvast 1998, Eddicks 2007 The mechanism of this action incompletely understood Increase in myocardial blood flow? Redistribution of local myocardial blood flow? Normalisation of the intrinsic cardiac nervous system?
Aims Assess the short-term effect of SCS On quantitative myocardial blood flow (MBF) and myocardial flow reserve (MFR) using positron emission tomography (PET) On ischemic wall motion abnormality by dobutamine echocardiography
Patients and methods Total of 19 (17 males) patients (age 68 ± 6,8 years, BMI 29 ± 4) with refractory angina were recruited 3 vessel disease in 100%, previous CABG in 100%, previous MI in 53%, EF>40% Examinations at baseline (SCS off) and after 3 weeks of continuous spinal cord stimulation (SCS on) Quantitative MBF (ml/g/min) by 15 O-H 2 O PET at rest, during adenosine stress and during cold pressor test Dobutamine echocardiography
PET imaging protocol PET scan Tracer injection Adenosine infusion Foot in ice water Rest Adenosine stress Cold pressor test 0 5 10 15 20 25 30 35 40 45 Time (min)
Results: Hemodynamic parameters during PET scans Heart rate (bpm) Baseline SCS Baselin e Mean arterial pressure (mmhg) SCS Rest 62±11 62±11 92±13 91±11 Adenosine Stress Cold pressor test 68±12 68±10 91±14 89±14 67±12 64±10* 102±13 100±11 *P=0.05
Global MBF at baseline and after SCS 2.0 Rest Stress MBF (ml/g/min) 1.5 1.0 0.5 MBF (ml/g/min) 3.0 2.0 1.0 0.0 P=0.052 0.0 P=0.103
Global MFR at baseline and after SCS MFR= MBF(Stress) MBF(Rest) 4 3 P=0.023 MFR 2 1,71 2,05 1 0
MFR Change in MBF and MFR in ischemic (MFR<2.0) and remote segments from baseline to after SCS Rest Stress MFR 1.0 MBF (ml/g/min) 0.5 0.0-0.5 P=0.035 Ischemia Remote P=0.005 0.5 0.0-0.5-1.0
Global MBF response (ΔMBF) to cold pressor test at baseline and after SCS 0.8 0.6 P=0.352 MBF (ml/g/min) 0.4 0.2 0.0-0.2-0.4
Dobutamine echocardiography Dobutamine infusion started 5 ug/kg/min and increased every 3 min to 10, 20, 30 and 40 ug/kg/min Significant increase in time to severe chest pain from 370±115 s to 472±119 s (P=0.0031) Significant improvement in longitudinal systolic strain at 370 s of infusion (-11.2% vs -13.5%, P=0.0007)
Conclusions In patients with refractory angina pectoris, spinal cord stimulation Increased myocardial flow reserve, especially in ischemic segments Prolonged appearance of chest pain and improved wall motion abnormalities induced by dobutamine Short term (3 weeks) SCS therapy has antiischemic effect The effects of more prolonged SCS therapy on MBF remain to be studied in the future