Blood pressure response to uncomplicated hemodialysis: the importance of changes in stroke volume.

BACKGROUND: The cause of blood pressure (BP) changes during uncomplicated hemodialysis (HD) has not been fully investigated. Controversy exists whether changes in BP result from changes in stroke volume (SV) or total peripheral resistance (TPR). METHODS: We investigated 19 patients using continuous BP monitoring (Portapres) and subsequent Modelflow analysis, yielding continuous SV, cardiac output (CO) and TPR values. Blood volume (BV) monitoring was also performed. For each patient, the sensitivity index (SI) was calculated. The SI is the slope of the curve depicting the relationship between the systolic BP (SBP) response and the BV response. The patients were divided into two groups: group A had an SI >1 which means a decrease in SBP in response to BV change, and group B had an SI <1. In these patients, SBP remained stable despite a BV change. RESULTS: Baseline characteristics and baseline values of all parameters were similar between the groups. In group A, SBP decreased by 25 +/- 19 mm Hg and in group B the SBP increased by 5.0 +/- 29 mm Hg (p < 0.05), while BV change was similar (10.6 +/- 4.9 and 11.2 +/- 4.2%, respectively). The difference in SBP response was caused by a different SV response (group A -44 +/- 16% and group B -26 +/- 18%, p = 0.04), while the TPR response was similar (71 +/- 27% in group A vs. 59 +/- 58% in group B). CONCLUSION: Patients responding with a BP decrease to BV reduction during uncomplicated HD differ in their SV response from patients with a stable BP.

ST segment depression criteria and the prevalence of silent cardiac ischemia in hypertensives.

The reported prevalence of silent cardiac ischemia as assessed by ambulatory electrocardiographic recording varies widely. The influence of the stringency of the analysis criteria has never been reported. We performed 24-hour, 12-lead ambulatory electrocardiographic recording in patients with hypertension but without proven coronary artery disease. The recordings were analyzed according to strict ST segment depression criteria adapted from the American College of Cardiology/American Heart Association guidelines and according to basic ST segment depression criteria adapted from studies with only concise descriptions of ambulatory electrocardiographic recording analysis. Also, we performed 24-hour ambulatory blood pressure monitoring. More than 4400 hours of ambulatory electrocardiographic recording and ambulatory blood pressure monitoring in 194 patients with hypertension were analyzed. Medication was withdrawn in 45% of the patients. The average systolic blood pressure during the day was 152+/-13 (mean+/-SD); diastolic blood pressure was 94+/-17 mm Hg. According to the basic ST segment depression criteria, we found a prevalence of silent ischemia of 11.3%, and with the strict criteria the prevalence was 5.2%. The patients who were considered positive according to the basic criteria but not according to the strict criteria (false-positive) in the majority of cases (58%) had depression of an elevated baseline ST segment. We found a lower prevalence of silent cardiac ischemia as assessed by ambulatory electrocardiographic recording than generally reported. The stringency of applied analysis criteria appear to play an important role in this outcome.

Diagnostic value of simultaneous non-invasive continuous, ambulatory finger blood pressure and electrocardiogram monitoring in a patient with hypertrophic obstructive cardiomyopathy.

BACKGROUND: The pathophysiology of hypertrophic obstructive cardiomyopathy (HOCM) is complex and heterogeneous, and it may be difficult to disentangle the various pathophysiologic properties leading to complaints. OBJECTIVES: To elucidate the sequence of acute pathophysiologic changes leading to complaints in a patient with HOCM. METHODS: Cardiopres measurements [the combination of non-invasive, continuous finger artery blood pressure monitoring, and three-lead electrocardiogram (ECG) recordings] were performed during physiologic, supine exercise--before and after replacement of metoprolol by verapamil. Within 24 h of the Cardiopres measurement standard Doppler echocardiography was performed. Finger artery pressure wave was analysed using Beatscope software (BMI-TNO, Amsterdam, The Netherlands), ST analysis was performed with H-Scribe (Mortara Instrument, Bilt, The Netherlands). RESULTS: Exercise under metoprolol: finger BP decreased from 130/65 mmHg to 90/60 mmHg, heart rate increased from 65 bpm to 100 bpm and ST analysis revealed significant ST depression in all leads. The occurrence of ST depression preceded the hypotension. Echocardiography showed a dynamic gradient of 70 mmHg. Exercise under verapamil: the patient had less complaints, BP increased from 125/60 mmHg to 165/65 mmHg, heart rate increased from 75 bpm to 107 bpm and ST analysis showed no ST depression > 1 mm. Echocardiography showed no change. CONCLUSIONS: The use of the Cardiopres during a physiological stimulus showed improvement in exercise capacity in a patient with HOCM, while the standard test, stress-echocardiography, showed no correlation with clinical status. The Cardiopres is a useful diagnostic and research tool, allowing non-invasive, ambulatory monitoring of blood pressure and ECG changes.