Objective: To test the hypothesis that B-type natriuretic peptide is elevated in patients with both lumbar spinal stenosis and cardiopulmonary dysfunction who reported sleep-interrupting low back pain, the "symptomatic group," as compared with an analogous cohort not experiencing nocturnal low back pain, i.e., the "control group." B-type natriuretic peptide is a hormonal product of the myocardium, which increases with an elevation in blood volume. Even without clinical symptoms, the more the myocardial stretch, the higher the B-type natriuretic peptide.
Design: In both groups, all of the patients were identified as having lumbar spinal stenosis and a history of cardiopulmonary dysfunction. However, all of the symptomatic group reported initially falling asleep and then experiencing sleep interrupting low back pain. However, in both groups, their cardiac status remained clinically stable. Main outcome measures included both the B-type natriuretic peptide titer and lumbar spinal magnetic resonance imaging.
Results: There were 10 patients with nocturnal pain and eight who were pain-free at night. The magnetic resonance imaging in both cohorts demonstrated a spectrum of moderate to severe lumbar spinal stenosis. Their previous cardiac history varied from the presence of arrhythmias to that of congestive heart failure. Other risk factors including age, among others, were similar in both cohorts. The mean B-type natriuretic peptide titer in the control group was 67.88 +/- 46.58 pg/ml. In the symptomatic group it was significantly elevated to 136.90 +/- 62.14 pg/ml.
Conclusions: In this clinical care series, the B-type natriuretic peptide titer was significantly increased in the symptomatic group as compared with the control group. The standard error of the mean was 19.65 in this group and 16.47 in the control group. An elevated B-type natriuretic peptide reflects a decrement in cardiac efficiency which may not be clinically evident. It also has a profound hypotensive effect because of its diuretic, natriuretic, and vascular dilatory properties. As a direct consequence of the increased right heart filling pressure, retrograde engorgement of the paravertebral plexus of veins surrounding the spinal neural elements may occur. Dilation of these valveless veins within an already stenotic spinal canal may induce the symptoms of Vesper's Curse, i.e., sleep-disrupting lumbar pain as a symptom of spinal stenosis in patients with a history of cardiopulmonary disease.