ABSTRACT
AIM: To investigate whether blood biomarkers measured routinely at hospital admission in myocardial infarction (MI) patients can improve the admission GRACE score for the composite endpoint of all-cause mortality and non-fatal MI at 6â¯months. METHODS: 2055 patients treated for MI in the Northwest clinics, the Netherlands, between 2013 and 2016 were examined. As part of the prevailing MI treatment protocol, 19 biomarkers were measured and the GRACE score was ascertained. Information on the composite endpoint was derived from municipal registries and electronic medical records. We applied elastic net logistic regression (LR) analysis to select biomarkers that had statistically significant additive prognostic value on top of the GRACE score. We then studied the prognostic performance of the LR model containing the GRACE score and the selected biomarkers. RESULTS: At six months follow-up 143 (6.96%) reached the composite endpoint. Nine variables were included in the final LR model: GRACE score, urea, sodium, potassium, alkaline phosphatase, LDL cholesterol, glucose, hemoglobin and C-reactive protein. This extended GRACE score model showed improved discrimination (C-statistic 0.76 vs 0.70, pâ¯=â¯<0.001) and classification (continuous net reclassification index 0.49, pâ¯<â¯0.001) compared with the GRACE score only. CONCLUSION: The ability of the GRACE score for detecting MI patients at high risk for mortality or MI within 6â¯months, was significantly improved by adding several biomarkers measured routinely at admission.
Subject(s)
Acute Coronary Syndrome/blood , Acute Coronary Syndrome/diagnosis , Myocardial Infarction/blood , Myocardial Infarction/diagnosis , Registries , Severity of Illness Index , Acute Coronary Syndrome/mortality , Aged , Aged, 80 and over , Biomarkers/blood , Cohort Studies , Female , Humans , Male , Middle Aged , Mortality/trends , Myocardial Infarction/mortality , Retrospective Studies , Risk AssessmentABSTRACT
BACKGROUND: The nurse practitioner may be the ideal healthcare worker to create a new environment and may facilitate in the process of expediting discharge and improving patient safety. They can play an intermediary role between the consultants, nurses and patients, thereby combining the aspects of care (nursing) and cure (physicians). METHOD: We describe the contribution and role of the nurse practitioner in a teaching hospital and provide an overview of the changes in care and cure that were facilitated by two nurse practitioners in the treatment of cardiac surgery patients or non-complicated acute coronary syndrome patients. RESULTS: The nurse-led clinic for postoperative patients has registered 1967 patients in the past 10 years. These patients were transferred at a mean of 5.5 days after their bypass operation. All patients had an uneventful clinical course in our hospital and were discharged alive. The period between discharge and outpatient clinic visit could be set at 4 weeks. The post-acute coronary syndrome (ACS) group included 1236 patients. Mortality in this patient cohort was 4% while 0.4% of these patients experienced a re-myocardial infarction. Additional surgery was needed in only 2% of these stable post-infarction patients. The mean length of stay was 5.9 ± 14.5 days. CONCLUSION: This observational study confirms that a nurse-led postoperative care unit and post-ACS care unit is feasible and effective for the treatment of patients returning from cardiac surgery or transferred after uncomplicated ACS to a general cardiology ward.
ABSTRACT
AIMS: To assess safety and efficacy of off-site percutaneous coronary intervention (PCI) in The Dutch invasive cardiovascular system. METHODS AND RESULTS: Descriptive single centre registry of elective and emergency PCI. Setting is a Dutch community hospital, 40 km north of Amsterdam, with an adherent population of 400,000 people. A Clinical follow up of Major Adverse Cardiac and Cerebral Events (MACCE) at 30 days post PCI is performed. The total number of participants eligible for PCI was 781 of whom 545 were men and 236 women. During a two-year period 781 PCI's were performed of which 298 were emergency and 483 elective. Acute complications occurred in 2.1% of participants. MACCE-free was 86.9% in the group with AMI and 95.8% in the elective group. CONCLUSIONS: Off-site PCI is feasible and safe in The Netherlands on the condition that specific key factors for success are taken into consideration.
Subject(s)
Angioplasty, Balloon, Coronary/statistics & numerical data , Hospitals, Community/statistics & numerical data , Myocardial Infarction/therapy , Angioplasty, Balloon, Coronary/adverse effects , Angioplasty, Balloon, Coronary/standards , Clopidogrel , Feasibility Studies , Female , Humans , Male , Middle Aged , Myocardial Infarction/drug therapy , Myocardial Infarction/epidemiology , Netherlands/epidemiology , Platelet Aggregation Inhibitors/therapeutic use , Registries , Risk Factors , Safety , Ticlopidine/analogs & derivatives , Ticlopidine/therapeutic use , Treatment OutcomeABSTRACT
BACKGROUND.: Based on experience from other countries, the Medical Centre Alkmaar was granted permission to start the first Dutch PCI programme without on-site cardiac surgery. The cardiology group of the Medical Centre Alkmaar started an off-site PCI programme in 2002 with only primary PCI in the first year and a full PCI programme from November 2003 onwards. We report the first Dutch experience with acute cardiac surgery following a failed PCI procedure in an off-site clinic. PATIENTS.: From October 2002 until February 2007, 2500 patients were treated by PCI in the Medical Centre Alkmaar. These patients were treated for an acute myocardial infarction (33%), acute coronary syndromes (37%) or progressive angina (30%). In this first series of off-site PCI in the Netherlands, the incidence of emergency cardiac surgery following failed PCI was 0.2% All five patients who needed emergency surgery underwent elective PCI for progressive stable coronary artery disease. No emergency surgery was needed for primary PCIs in patients with an acute myocardial infarction. All patients survived emergency surgery following failed PCI. CONCLUSION.: Adherence to the Dutch guidelines of interventional cardiology with protocols describing a close collaboration with cardiac surgeons and an immediate availability of rapid ground transportation are mandatory when performing off-site PCI. This series extends the current expertise of emergency surgery after failed PCI to off-site clinics. With appropriate settings, off-site PCI may not be associated with an increase in the risk of adverse events. (Neth Heart J 2007;15:173-7.).
ABSTRACT
A drug-eluting stent was implanted in four patients, a man aged 67 and a woman aged 42 with acute myocardial infarction, a woman aged 41 with unstable angina pectoris and a man aged 41 with stable angina pectoris. All suffered stent thrombosis after discontinuation (in three cases prematurely) of clopidogrel therapy. Reasons for discontinuation included allergic reaction, a dental procedure and refusal of reimbursement by the insurer. In order to restore stent patency they were treated by percutaneous coronary intervention and all patients suffered irreversible myocardial damage. Combination therapy using acetylsalicylic acid and clopidogrel during and after angioplasty for the prevention of long- and short-term complications is necessary. Stent thrombosis after drug-eluting stent implantation usually occurs within 1-4 weeks following discontinuation ofantiplatelet medication. These cases stress the importance of antiplatelet therapy after stent implantation. Physicians, dentists and patients must be aware of the risk of the early discontinuation ofantiplatelet therapy.
Subject(s)
Angina Pectoris/therapy , Myocardial Infarction/therapy , Platelet Aggregation Inhibitors/therapeutic use , Stents , Thrombosis/etiology , Ticlopidine/analogs & derivatives , Adult , Aged , Angina Pectoris/complications , Angina Pectoris/surgery , Aspirin/therapeutic use , Clopidogrel , Female , Humans , Male , Myocardial Infarction/complications , Myocardial Infarction/surgery , Ticlopidine/therapeutic useABSTRACT
BACKGROUND: Anticoagulation after coronary stenting is essential to prevent stent thrombosis. Drug-eluting stents, which are the preferred therapy, may be associated with a higher tendency for stent thrombosis. METHODS: Patients who underwent coronary stent placement and presented with late stent thrombosis are described. RESULTS: Eight patients with stent thrombosis are presented. Early discontinuation of the antithrombotic medication is associated with the occurrence of these complications. CONCLUSION: Long-term antithrombotic therapy seems essential to prevent stent thrombosis, especially for patients treated with drug-eluting stents.
ABSTRACT
At present, there is no reliable antianginal drug therapy for patients with cardiac syndrome X. Therefore, the effect of electrical neuromodulation on refractory angina pectoris and myocardial perfusion in cardiac syndrome X was assessed. Eight patients (aged 55+/-7 years) with heterogeneous myocardial perfusion and no esophageal abnormalities were included. The subjects were nonresponders to antianginal drug therapy. Angina pectoris attacks and myocardial perfusion dynamics were evaluated by positron emission tomography at baseline and following 4 weeks of (transcutaneous electrical nerve stimulation) TENS. Following TENS there was a reduction of angina pectoris episodes (baseline 20+/-3, TENS 3+/-1; p=0.012), and short acting nitroglycerin intake per week (baseline 10+/-3, TENS 2+/-1; p=0.008). The rate pressure product (mmHg min(-1)) during the cold pressor test (CPT) was reduced during TENS (baseline 12800+/-1200, TENS 11500+/-900; p=0.02). Following TENS, the perfusion reserve ratio between rest and dipyridamole flow increased (baseline 1.59+/-0.15, TENS 1.90+/-0.11 ml min(-1)x 100g; p=0.05). The coronary vascular resistance had a trend towards a reduction (baseline 0.96+/-0.04, TENS 0.85+/-0.06 mmHg min(-1)x 100 g/ml; p=0.06) during CPT. This observation may suggest that neurostimulation improves angina pectoris with a concomitant improvement of myocardial perfusion in cardiac syndrome X.
Subject(s)
Angina Pectoris/therapy , Coronary Circulation , Microvascular Angina/therapy , Myocardial Ischemia/therapy , Transcutaneous Electric Nerve Stimulation , Adult , Coronary Circulation/drug effects , Dipyridamole/pharmacology , Female , Humans , Male , Microvascular Angina/drug therapy , Microvascular Angina/physiopathology , Middle Aged , Nitroglycerin/pharmacology , Research Design , Tomography, Emission-Computed , Treatment Outcome , Vasodilator Agents/pharmacologyABSTRACT
BACKGROUND: Recent findings imply prognostic significance of intracoronary acetylcholine infusion for endothelial function testing. We evaluated whether routine use of this test in coronary angiography patients is safe. METHODS: Patients undergoing a first diagnostic coronary angiography were selected to receive intracoronary acetylcholine for endothelial function evaluation. The relation between adverse reactions during infusion and risk factors was analyzed with a logistic regression model. Included in the multiple logistic regression model were the variables with a univariate P value < 0.20. RESULTS: Adverse reactions occurred in 16% (49/299) of the patients. This included two life-threatening events caused by occlusive spasm and flow limitation in the left coronary artery. Other adverse events were chest pain (n = 38), AV block or sinus bradycardia (n = 10), dyspnea (n = 3). Adverse reactions were more likely to occur in patients younger than 60 years of age (relative risk, 5.6 [2.2-14.3]). CONCLUSION: Intracoronary acetylcholine infusion is safe, but may lead to serious adverse reactions. Care should be taken especially in patients younger than 60 years of age. Routine use of acetylcholine infusion can thus only be justified if it has important prognostic significance. This has to be proven further in large prospective studies.
Subject(s)
Acetylcholine/adverse effects , Coronary Angiography , Acetylcholine/administration & dosage , Aged , Contraindications , Coronary Vasospasm/diagnosis , Coronary Vessels/drug effects , Electrocardiography , Female , Humans , Infusions, Intra-Arterial , Logistic Models , Male , Middle Aged , Monitoring, IntraoperativeABSTRACT
The present study assessed the reoccurrence of myocardial ischemia after withholding electrical neurostimulation. After randomization, in the study or withdrawal group, spinal cord stimulation (SCS) was set active during the first 4 weeks, followed by 4 weeks of withholding stimulation. In the control group, SCS was switched off during 4 weeks before the end of the study. The control group had no crossover period. Measurements were done at baseline, then after 4 and 8 weeks. The first periods at 4 weeks of each sequence of both groups were compared. In addition, a comparison of clinical variables was performed between the study group 4 weeks after withholding stimulation and the control group 4 weeks following randomization. A total number of 24 patients with refractory angina and an implanted spinal cord stimulator were included in the study (n = 12) and control group. Angina pectoris complaints, nitroglycerin intake, ischemia, and heart rate variability using 48-hour ambulatory electrocardiographic monitoring were assessed. In addition, neurohormonal status and symptom-limited aerobic capacity were evaluated. There was no increase of anginal complaints or ischemia after withholding stimulation. Neurohormonal levels and aerobic capacity were not altered. We conclude that there is no adverse clinical rebound phenomenon after withholding neurostimulation in patients with refractory angina pectoris.
Subject(s)
Coronary Disease/therapy , Electric Stimulation Therapy , Aged , Angina Pectoris/physiopathology , Coronary Disease/physiopathology , Electrocardiography, Ambulatory , Epinephrine/blood , Exercise Test , Female , Follow-Up Studies , Heart Rate , Humans , Male , Middle Aged , Myocardial Ischemia/physiopathology , Norepinephrine/blood , Oxygen Consumption , Prospective Studies , Recurrence , Respiratory Function Tests , Sympathetic Nervous System/physiopathology , Time FactorsABSTRACT
Patients with symptomatic small vessel coronary artery disease may be inadequate candidates for revascularization procedures. They may suffer from refractory angina, which does not respond to maximal anti-anginal drug therapy. In addition to patients with end stage coronary artery disease and syndrome X, this newly defined group of subjects with an isolated stenosis of a small coronary artery may benefit from electrical neurostimulation. We describe two patients with intractable angina caused by a significant narrowing of a diagonal branch. This treatment modality should be considered as an alternative method for unsatisfactory revascularization procedures.
Subject(s)
Angina Pectoris/etiology , Angina Pectoris/therapy , Coronary Stenosis/complications , Disabled Persons , Pericardium , Transcutaneous Electric Nerve Stimulation , Aged , Angina Pectoris/physiopathology , Female , Humans , Male , Middle Aged , Treatment OutcomeABSTRACT
BACKGROUND: Spinal cord stimulation is known to be a successful treatment for chronic intractable angina pectoris. Its effect may be anti-ischemic. It is uncertain if the clinical effect is partly caused by a placebo effect of surgery for implantation of a stimulator. In this study, clinical efficacy is investigated, together with a possible placebo effect. METHODS AND RESULTS: Efficacy of spinal cord stimulation as a treatment for chronic intractable angina pectoris was studied for 6 weeks in 13 treated patients and 12 control patients with chronic angina. Assessments were exercise capacity and ischemia, daily frequency of anginal attacks and nitrate tablet consumption, and quality of life (perceived quality of life and pain). Compared with control, exercise duration (P =.03) and time to angina (P =.01) increased; anginal attacks and sublingual nitrate consumption (P =.01) and ischemic episodes on 48-hour electrocardiogram (P =.04) decreased. ST-segment depression on the exercise electrocardiogram decreased at comparable workload (P =.01). Anginal attacks and consumption of sublingual nitrates decreased (P =.01), perceived quality of life increased (P =.03), and pain decreased (P =.01). CONCLUSIONS: Spinal cord stimulation is effective in chronic intractable angina pectoris, and its effect is exerted through anti-ischemic action. Efficacy is unlikely to be explained as a placebo effect from surgery.
Subject(s)
Angina Pectoris/therapy , Electric Stimulation Therapy , Spinal Cord , Aged , Chronic Disease , Electrocardiography, Ambulatory , Electrodes, Implanted , Exercise Test , Female , Humans , Male , Middle Aged , Pain, Intractable , Quality of Life , Treatment OutcomeABSTRACT
To study the effect of transcutaneous electrical nerve stimulation (TENS) on coronary vasomotion, patients with New York Heart Association class III angina pectoris and significant single-vessel left coronary artery disease and who were also scheduled for elective percutaneous transluminal coronary angioplasty, were allocated to a study group (precordial actual TENS, n = 10) and a control group (precordial simulated TENS, n = 5, and TENS on the back, n = 3). Coronary volumetric flow was assessed in the stenotic and nonstenotic coronary artery before and after neurostimulation. The diameter (in millimeters) of the stenotic coronary artery was reduced in the study group after actual TENS (from 2.73 +/- 0.55 by 0.12 +/- 0.11; p = 0.008). In the nonstenotic coronary artery, the diameter increased in the study group (from 2.64 +/- 0.43 by 0.24 +/- 0.15; p = 0.01). In both the stenotic and nonstenotic coronary arteries, no effect was shown on the average peak velocity (centimeters per second) in the study group. The coronary volumetric flow (milliliters per minute) was reduced in the stenotic artery of the study group (from 62 +/- 18 by 8 +/- 7; p = 0.007). In the nonstenotic coronary artery, volumetric flow increased in the study group (from 57 +/- 18 by 11 +/- 10; p = 0.007). In the control group, simulated TENS and TENS on the back had no effect on the diameter of the artery, average peak velocity, or volumetric flow. In addition, in all patients, TENS had no effect on the total volumetric flow of the left coronary artery and hemodynamic variables during the study period. This observation suggests that TENS modulates regional coronary vasomotion in patients with coronary artery disease.
Subject(s)
Angina Pectoris/therapy , Coronary Circulation , Coronary Disease/physiopathology , Transcutaneous Electric Nerve Stimulation , Aged , Angina Pectoris/etiology , Angina Pectoris/physiopathology , Blood Volume , Coronary Disease/complications , Coronary Vessels/physiopathology , Female , Hemodynamics , Humans , Male , Middle Aged , Reproducibility of Results , Vasomotor SystemABSTRACT
BACKGROUND AND HYPOTHESIS: Spinal cord stimulation is an effective treatment for chronic refractory angina pectoris. Its efficacy is related to an anti-ischemic action, possibly as a result of modulation of the autonomic nervous system. Therefore, the influence of spinal cord stimulation on the autonomic nervous system and myocardial ischemia was prospectively studied in 19 consecutive patients with intractable angina pectoris. METHODS: Patients were included when demonstrating > 0.1 mV STsegment depression on the exercise electrocardiogram (ECG) during two separate treadmill tests. After enrollment, heart rate variability together with ischemic indices were studied with 48 h ambulatory ECG monitoring. Assessments were made at baseline and after 6 weeks of spinal cord stimulation therapy. RESULTS: After 6 weeks, no significant changes in heart rate variability were detected. However, ischemic indices on the ambulatory ECG, as well as anginal attacks and consumption of sublingual nitrate tablets, were significantly decreased. CONCLUSION: Autonomic modulation assessable with heart rate variability analysis may not be the explanatory mechanism of action for the decrease of anginal attacks and ischemia, exerted by spinal cord stimulation used as an adjuvant therapy in patients with chronic intractable angina pectoris.
Subject(s)
Angina Pectoris/therapy , Electric Stimulation Therapy/methods , Electrocardiography, Ambulatory , Heart Rate/physiology , Myocardial Ischemia/physiopathology , Spinal Cord , Angina Pectoris/physiopathology , Autonomic Nervous System/physiopathology , Chronic Disease , Electrodes, Implanted , Exercise Test , Female , Follow-Up Studies , Heart/innervation , Humans , Male , Middle Aged , Myocardial Ischemia/therapy , Prospective Studies , Spinal Cord/physiology , Treatment OutcomeABSTRACT
For more than a decade, spinal cord stimulation (SCS) has been used as an adjuvant treatment for patients who are unresponsive to conventional therapies for angina pectoris. Many studies showed that SCS has both electro-analgesic and anti-ischemic effects. Nonetheless, the biological substrates by which SCS acts have not yet been unraveled, although recently areas in the brain have been described that show changes in blood flow, following SCS, and during provocation of angina. In search of a putative mechanism of action of SCS, we hypothesized that SCS affects processing of nociceptive information within the central nervous system (CNS). Moreover, it may alter the limbic system activity that maintains the balance between sympathetic and parasympathetic activity in the heart. Hence, we have developed a rat model to investigate its suitability for studying the induction of neural activity during SCS. To characterize neural activity, we used the expression of both the immediate early gene c-fos and the heat shock protein 72 (HSP72). c-Fos was used to identify structures in the CNS affected by SCS, and HSP72 was applied in order to ascertain whether SCS might operate as a stressor. In 20 halothane-anesthetized male Wistar rats, two electrodes were placed epidurally, one at the C7 level and the other at the T2 level. Two days after surgery, the rats were either stimulated "treated" animals, n = 10) or used as controls ("unstimulated" = "sham," n = 10) in random order. Furthermore, we studied the effect of SCS on behavior in five treated and five control rats. Three hours after stimulation, the rats were euthanized and the brain and spinal cord were removed. The treated group showed regional increased c-fos expression in regions of the limbic system (periaqueductal gray, paraventricular hypothalamic nucleus, paraventricular thalamic nucleus, central amygdala, agranular and dysgranular insular cortex, (peri)ambiguus, nucleus tractus solitarius, and spinal cord) that are involved in the processing of pain and cardiovascular regulation, among other things. Moreover, in both treated rats and controls, HSP72-expression was found in the endothelium of the enthorhinal cortex, the amygdala, and the ventral hypothalamus, but not in the neurons. Finally, treated animals were significantly more alert and active than controls. In conclusion, the rat model we developed appears to be suitable for studying potential mechanisms through which SCS may act. In addition, SCS affects c-fos expression in specific parts of the brain known to be involved in regulation of pain and emotions. HSP72-expression is limited to the endothelium of certain parts of the CNS and thereby excludes physical stress effects as a potential mechanism of SCS.
ABSTRACT
Spinal cord stimulation applied at thoracic level 1 (T1) has a neurally mediated anti-anginal effect based on anti-ischaemic action in the myocardium. Positron emission tomography was used to study which higher brain centres are influenced by spinal cord stimulation. Nine patients with a spinal cord stimulator for angina pectoris were studied using H(2)(15)O as a flow tracer. Relative changes in regional cerebral blood flow related to stimulation compared with non-stimulation were assessed and analysed using the method of statistical parametric mapping. Increased regional cerebral blood flow was observed in the left ventrolateral periaqueductal grey, the medial prefrontal cortex [Brodmann area (BA) 9/10], the dorsomedial thalamus bilaterally, the left medial temporal gyrus (BA 21), the left pulvinar of the thalamus, bilaterally in the posterior caudate nucleus, and the posterior cingulate cortex (BA 30). Relative decreases in rCBF were noticed bilaterally in the insular cortex (BA 20/21 and BA 38), the right inferior temporal gyrus (BA 19/37), the right inferior frontal gyrus (BA 45), the left inferior parietal lobulus (BA 40), the medial temporal gyrus (BA 39) and the right anterior cingulate cortex (BA 24). It is concluded that spinal cord stimulation used as an additional treatment for angina applied at T1 modulates regional cerebral blood flow in brain areas known to be associated with nociception and in areas associated with cardiovascular control.
Subject(s)
Angina Pectoris/physiopathology , Cerebrovascular Circulation/physiology , Spinal Cord/physiology , Aged , Cerebrovascular Circulation/drug effects , Electric Stimulation , Female , Humans , Male , Middle Aged , Tomography, Emission-ComputedABSTRACT
The anatomy of cardiac activity-regulating circuitry was studied with retrograde transneuronal viral labelling after pseudorabies virus injections into different parts of the rat heart. Transection of the spinal cord at Th1 was used to reveal selectively the parasympathetic neuronal networks. Virus-labelled sympathetic preganglionic cells were found in the Th1-Th7 thoracic intermediolateral cell groups, with some additional infections at Th8-Th11 after inoculations of the ventricular myocardium. After ventricular injections the thoracic spinal labelling pattern was bilateral and after right atrial infection it was contralateral. Approximately 20% of the parasympathetic preganglionic cells were located in the dorsal motor vagus nucleus; the rest occupied positions in the peri-ambiguus area ventrolateral to the nucleus ambiguus. Here and in the ventrolateral reticular formation myocardiotopy was found. Supraspinal transneuronal infections were bilateral, showed no apparent side dominance and were found in the nucleus of the solitary tract, the area postrema, the raphe nuclei, the A5 group, the parabrachial region, the periaqueductal grey, the hypothalamus, the amygdala and the cortex, in particular the anterior cingulate, the frontal, prelimbic, infralimbic and insular cortices. Spinal transections at Th1 reduced the number of labelled cells, gave a right side labelling dominance and affected the infection patterns in the ventrolateral reticular area, the raphe nuclei, the periaqueductal grey matter, the perifornical and retrochiasmatic area and the rostral parts of the insular cortex. The latter structures are linked selectively to the sympathetic innervation of the heart. The anatomical and functional aspects of these findings are discussed in relation to the autonomic control of heart activity.
Subject(s)
Heart/innervation , Herpesvirus 1, Suid/physiology , Nerve Fibers/physiology , Neurons/physiology , Parasympathetic Nervous System/physiology , Sympathetic Nervous System/physiology , Animals , Male , Rats , Rats, Wistar , Vagus Nerve/physiologyABSTRACT
The treatment of angina pectoris as a symptom of coronary artery disease usually is focused on restoring the balance between oxygen demand and supply of the myocardium by administration of drugs interfering in heart rate, cardiac pre- and afterload, and coronary vascular tone. For nonresponders to drug therapy or for those with jeopardized myocardium, revascularization procedures such as coronary bypass surgery and percutaneous transluminal coronary angioplasty are at hand. However, the atherosclerotic process is not stopped by these therapies and, at longer terms, angina may recur. It is not always possible to revascularize all the patients who do not positively react to medical treatment. Those with angina, not responding to adequate medication and who are not suitable anymore for revascularization, are considered to suffer from refractory angina pectoris. This group of patients has a poor quality of life, for their exercise tolerance is severely afflicted. For these patients, neurostimulation has been described repeatedly as an effective and safe therapy. The mechanism of action of neurostimulation is not completely known, but recent studies suggest an anti-ischemic effect, exerted through changes in myocardial blood flow. As soon as its safety is sufficiently established, it may become a useful alternative in the treatment of refractory angina pectoris.
Subject(s)
Angina Pectoris/therapy , Transcutaneous Electric Nerve Stimulation , Angina Pectoris/drug therapy , Angina Pectoris/physiopathology , Coronary Circulation , Humans , Myocardium/metabolism , Regional Blood Flow , Treatment Failure , Treatment OutcomeABSTRACT
Spinal cord stimulation in angina pectoris increases exercise capacity and reduces both anginal attacks and ischemic electrocardiographic signs. This suggests an anti-ischemic action, perhaps through changes in myocardial blood flow. In 9 patients, regional myocardial blood flow was studied with positron emission tomography before and after 6 weeks of spinal cord stimulation, both at rest and during a dipyridamole stress test. Frequency of anginal attacks and consumption of short-acting nitrates were assessed by patient diaries. Exercise duration and time to angina were measured with treadmill exercise tests. After 6 weeks of stimulation, both frequency of daily anginal attacks and nitrogen consumption decreased (3.7 +/- 1.7 vs 1.4 +/- 1.0 [p <0.01] and 2.8 +/- 2.2 vs 1.1 +/- 1.2 tablets [p = 0.01], respectively); exercise duration and time to angina increased (358 +/- 165 vs 493 +/- 225 seconds [p <0.01] and 215 +/- 115 vs 349 +/- 213 seconds [p = 0.02], respectively); and ST-segment depression during dipyridamole stress testing was reduced (0.17 [0 to 0.5] mV vs 0.09 [0 to 0.2] mV, p = 0.04) (all data mean +/- SD). Total resting blood flow remained unchanged (115 +/- 29 vs 127 +/- 31 ml/min/100 g, p = 0.31), but flow reserve decreased (146 +/- 43% vs 122 +/- 39%, p = 0.04). The coefficient of variation of flow, representing flow heterogeneity, decreased after treatment, both at rest (20.1 +/- 3.8% vs 17.4 +/- 2.6%, p = 0.04) and after dipyridamole stress (26.2 +/- 4.4% vs 22.9 +/- 5.5%, p = 0.02). Thus, spinal cord stimulation is clinically effective due to homogenization of myocardial blood flow. Since flow reserve decreases despite clinical improvement, the dipyridamole effect may be blunted by spinal cord stimulation.