Non-invasive continuous monitoring of cardiac output could be very useful in clinical care and in research settings, particularly in elderly subjects. We studied whether Finapres arterial pulse wave analysis with Modelflow is a reliable non-invasive method for the assessment of cardiac output in healthy elderly subjects. We compared Modelflow cardiac output (MFCO) with thermodilution cardiac output (TDCO) in 28 healthy subjects, aged 70+/-4 years (mean+/-S.D.). TDCO was measured during right-sided heart catheterization, while MFCO was calculated with Modelflow(R) software from non-invasive arterial Finapres blood pressure, which was measured simultaneously. The two methods were compared using a paired t-test, by Pearson correlation, and by Bland-Altman analysis. TDCO was 6.4+/-1.1 litres/min (mean+/-S.D.) and MFCO was 4.7+/-1.3 litres/min (P<0.001). There was no significant correlation between MFCO and TDCO (r=0.28, P=0.13). Mean difference (bias) was -1.7 litres/min (S.E.M. 0.27 litres/min), with an S.D. (precision) of 1.5 litres/min. The 95% limits of agreement were -4.6 to +1.1 litres/min. In conclusion, non-invasive MFCO values differed significantly from and showed no significant correlation with invasively determined TDCO values in the normal range. Although simple, non-invasive and patient-friendly, the Modelflow method is inaccurate for assessment of cardiac output without invasive calibration.

In the present study, we assessed whether elevated (> or =15 mmHg) PCWP (pulmonary capillary wedge pressure) can be detected using the blood pressure response to the Valsalva manoeuvre in a group of elderly patients with various cardiac disorders, including atrial fibrillation and valvular heart disease, and healthy elderly controls. The Valsalva manoeuvre was performed in 93 patients (71+/-4 years) and 28 healthy controls (70+/-4 years) undergoing right-sided cardiac catheterization. Blood pressure was measured non-invasively with Finapres. PPR (pulse pressure ratio), the ratio of minimum pulse pressure during phase 2 and maximum pulse pressure during phase 1 of the Valsalva manoeuvre, was correlated with PCWP (r=0.63, P<0.001). The area under the receiver operator characteristic curve of PPR with elevated PCWP was 0.85 (P<0.001). For PPR=0.62, sensitivity for elevated PCWP was 80%, specificity was 79%, positive predictive value was 76% and negative predictive value was 83%. Correlation of PPR with PCWP and the ability of PPR to detect elevated PCWP was present in atrial fibrillation, heart failure and valvular heart disease. In conclusion, PPR is a sensitive and specific instrument to diagnose elevated PCWP non-invasively in a large group of elderly patients with various cardiac disorders. This makes the Valsalva manoeuvre a useful non-invasive tool for diagnosing heart failure, applicable in elderly patients with common cardiac disorders, such as atrial fibrillation and valvular heart disease.

The blood pressure response to the Valsalva manoeuvre is related to pulmonary capillary wedge pressure (PCWP) and can be used to diagnose heart failure. However, this has never been studied specifically in the elderly, in whom the prevalence of heart failure is highest. Furthermore, normal values of the Valsalva manoeuvre are lacking. We aimed to obtain normal values of PCWP and the blood pressure response to the Valsalva manoeuvre in elderly subjects. Therefore, 28 healthy subjects, aged 70 +/- 4 years, performed Valsalva manoeuvres before and after anti-G garment inflation, which was used for temporary increase of PCWP. Before inflation, PCWP was 9.8 +/- 1.9 mmHg in supine and 8.9 +/- 2.1 in semi-recumbent position. From the blood pressure response, measured with Finapres, the systolic blood pressure ratio (SBPR), pulse pressure ratio (PPR), stroke volume ratio (SVR) and heart rate ratio (HRR) were calculated. In supine position, SBPR was 0.76 +/- 0.11, PPR 0.51 +/- 0.16, SVR 0.42 +/- 0.11, and HRR 1.17 +/- 0.12. Semi-recumbently, SBPR was 0.74 +/- 0.10, PPR 0.46 +/- 0.14, SVR 0.41 +/- 0.10, and HRR 1.24 +/- 0.23. After inflation of the anti-G garment, the areas under the Receiver Operator Characteristics curves of SBPR, PPR and SVR for elevated (> or = 15 mmHg) PCWP were >0.85 in supine position. In conclusion, this is the first study to obtain normal values of the blood pressure response to the Valsalva manoeuvre and PCWP in healthy elderly subjects, which is essential for the interpretation of patient data. The Valsalva manoeuvre showed significant discriminatory power in the detection of elevated PCWP, which underscores its potential in the non-invasive diagnosis of heart failure.

Background and aims: Heart failure is primarily a disorder of the elderly. To investigate a non-invasive method to diagnose heart failure in the elderly, right-sided catheterisation was needed in healthy elderly subjects. We studied the feasibility of recruitment of healthy elderly subjects for this invasive investigation and aimed to identify the factors important for recruitment and for successful participation. Methods: Healthy subjects, aged ≥65 years, were invited by advertisement in a local newspaper to participate in an invasive study, preceded by extensive medical examination. An experienced research nurse provided coaching and care on an individual basis. Motivation to participate, satisfaction and the expected and perceived burden were assessed with a questionnaire before and after catheterisation. Results: From 180 subjects responding, 53 were invited for screening of whom 38 were included. Cardiovascular examination was the most important reason for participation. The questionnaire showed considerable satisfaction about the information and care given and about participating in the study in general. Conclusions: Recruitment of healthy elderly subjects for an invasive cardiovascular study is feasible. Individual coaching contributed to the satisfaction experienced. The appointment of an experienced research nurse appears important for successful recruitment and participation of healthy elderly subjects in an invasive cardiovascular study.

stress once more that, without calibration, Modelflow2 CO should be expressed as relative changes from its starting value.

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