LETTER
The added diagnostic value of procalcitonin in elderly patients To the Editor: Lee and collaborators performed an informative systematic review and meta-analysis of the value of procalcitonin (PCT) to diagnose bacterial infection in elderly patients (1). PCT had about the same value to rule in or rule out the diagnosis, with a positive likelihood ratio at 5 and a negative LR at 0.2. Lee and collaborators correctly point out that these results assess the diagnostic value of PCT viewed in isolation, whereas clinicians always interpret PCT results among the other available clinical, biological, microbiological and imaging data. The authors therefore call for clinical trials to assess whether the incorporation of PCT to the already available information would improve outcomes. This type of studies would indeed achieve the highest level of evidence according to the architecture of diagnostic research proposed by the proponent of evidence-based medicine (2). However, it is possible to approach the added value of PCT more simply. We tried to
do so in our study on the topic (3), which is included in the meta-analysis but without any mention to these analyses. For instance, 33/112 patient had a PCT over 0.51 lg/l: this result was useless in 22 patients (infection already ruled in on clinical grounds), misleading in eight patients (no infection) and appropriately pointing to a nonobvious bacterial infection in three patients. The signal-to-noise ratio of a positive PCT is therefore very low. Low values of PCT were no more informative. O. Steichen,1,2,3 AP-HP Tenon Hospital Internal Medicine Department F-75020 Paris France 2 Universite Pierre et Marie Curie-Paris 6 Faculty of Medicine F-75006 Paris France 3 INSERM U1142 LIMICS F-75006 Paris France E-mail: [email protected]
1
References 1 Lee SH, Chan RC, Wu JY, Chen HW, Chang SS, Lee CC. Diagnostic value of procalcitonin for bacterial infection in elderly patients - a systemic review and meta-analysis. Int J Clin Pract 2013; 67: 1350–7. 2 Sackett DL, Haynes RB. The architecture of diagnostic research. BMJ 2002; 324: 539–41. 3 Steichen O, Bouvard E, Grateau G, Bailleul S, Capeau J, Lefevre G. Diagnostic value of procalcitonin in acutely hospitalized elderly patients. Eur J Clin Microbiol Infect Dis 2009; 28: 1471–6.
Disclosure None. doi: 10.1111/ijcp.12392
LETTER
Extracorporal life support (ECLS) in acute ischaemic cardiogenic shock To the Editor: In spite of rescue percutaneous coronary intervention (PCI), acute myocardial infarction (AMI) may lead to severe deterioration of left ventricular function triggering cardiogenic shock. Even application of high dosages of catecholamines or levosimendan (1) may not provide hemodynamic stabilisation in patients with severe cardiogenic shock because of AMI since catecholamines may further aggravate myocardial stress (2,3). Furthermore, intra-aortic balloon pump (IABP) does not provide significant advantage regarding survival in these patients (4). Thus, other strategies are needed in the life-threatening situation of progressive cardiogenic shock. Extra-corporal life support (ECLS) has been established several decades ago (5) and is used for transient stabilisation of the circulation or for bridging to transplantation (6). After canulation of the venous system, up to 6 litres of blood per minute are circulated and oxygenated via a turbine and reinfused into the femoral artery. Animal studies suggest that ventricular unloading reduces left ventricular wall stress und decreases myocardial infarct size (7). Here, we performed a retrospective study addressing the hypothesis that ECLS ª 2014 John Wiley & Sons Ltd Int J Clin Pract, April 2014, 68, 4, 529–531
might provide an option as bridge to recovery in patients with progressive cardiogenic shock after successful revascularisation. We hypothesised that intermittent ventricular unloading by ECLS therapy and paused or reduced application of catecholamines yields enhanced recovery of damaged myocardium. We conducted a retrospective study of all patients who have been treated with ECLS for cardiogenic shock because of acute myocardial ischaemia at our 19-bed single-centre cardiology intensive care unit from February 2012 to April 2013. During this time period, 12 patients were treated with ECLS (see Table 1). Inclusion criteria were progressive cardiogenic shock defined as persistent hypotension (systolic blood pressure < 90 mmHg in spite of cumulative catecholamine dosage exceeding 2.0 mg per hour) and successful PCI. Exclusion criteria were technical impossibility of ECLS implantation. ECLS implantation was performed in one case before PCI, in nine patients immediately after PCI in the catheterisation laboratory and in two patients 24 and 48 h after PCI with IABP bridging. ECLS implantation was performed under general anaesthesia by an interdisciplinary team consisting of cardiac surgeons, perfusionists and
cardiologists. Femoral artery and vein were used as cannula puncture sites. We compared the patients treated with ECLS to a control group, which comprised all consecutive patients with cardiogenic shock who were treated with catecholamines and IABP after PCI at our intensive care unit from January 2011 to January 2012. Outcome measures were survival 30 days after ECLS implantation and ECLS or IABP correlated complications. Comparisons between two groups concerning baseline characteristics were performed using the unpaired Student’s t-test or the Pearson’s chi-squared test. Data were defined statistically significant at a value of P < 0.05. The Kaplan– Meier method and Log Rank test were used for survival analysis. Data are expressed as mean standard deviation. Our analysis was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments. Since we performed a post hoc analysis, ethical approval or informed consent were not necessary. In the ECLS group, 10 patients were males (10 in the IABP group) and the mean age was 54.8 13.3 (68.3 12.2) years. All of them underwent successful percutaneous coronary revascularisation. Eight (10) patients
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The added diagnostic value of procalcitonin in elderly patients To the Editor: Lee and collaborators performed an informative systematic review and meta-analysis of the value of procalcitonin (PCT) to diagnose bacterial infection in elderly patients (1). PCT had about the same value to rule in or rule out the diagnosis, with a positive likelihood ratio at 5 and a negative LR at 0.2. Lee and collaborators correctly point out that these results assess the diagnostic value of PCT viewed in isolation, whereas clinicians always interpret PCT results among the other available clinical, biological, microbiological and imaging data. The authors therefore call for clinical trials to assess whether the incorporation of PCT to the already available information would improve outcomes. This type of studies would indeed achieve the highest level of evidence according to the architecture of diagnostic research proposed by the proponent of evidence-based medicine (2). However, it is possible to approach the added value of PCT more simply. We tried to
do so in our study on the topic (3), which is included in the meta-analysis but without any mention to these analyses. For instance, 33/112 patient had a PCT over 0.51 lg/l: this result was useless in 22 patients (infection already ruled in on clinical grounds), misleading in eight patients (no infection) and appropriately pointing to a nonobvious bacterial infection in three patients. The signal-to-noise ratio of a positive PCT is therefore very low. Low values of PCT were no more informative. O. Steichen,1,2,3 AP-HP Tenon Hospital Internal Medicine Department F-75020 Paris France 2 Universite Pierre et Marie Curie-Paris 6 Faculty of Medicine F-75006 Paris France 3 INSERM U1142 LIMICS F-75006 Paris France E-mail: [email protected]
1
References 1 Lee SH, Chan RC, Wu JY, Chen HW, Chang SS, Lee CC. Diagnostic value of procalcitonin for bacterial infection in elderly patients - a systemic review and meta-analysis. Int J Clin Pract 2013; 67: 1350–7. 2 Sackett DL, Haynes RB. The architecture of diagnostic research. BMJ 2002; 324: 539–41. 3 Steichen O, Bouvard E, Grateau G, Bailleul S, Capeau J, Lefevre G. Diagnostic value of procalcitonin in acutely hospitalized elderly patients. Eur J Clin Microbiol Infect Dis 2009; 28: 1471–6.
Disclosure None. doi: 10.1111/ijcp.12392
LETTER
Extracorporal life support (ECLS) in acute ischaemic cardiogenic shock To the Editor: In spite of rescue percutaneous coronary intervention (PCI), acute myocardial infarction (AMI) may lead to severe deterioration of left ventricular function triggering cardiogenic shock. Even application of high dosages of catecholamines or levosimendan (1) may not provide hemodynamic stabilisation in patients with severe cardiogenic shock because of AMI since catecholamines may further aggravate myocardial stress (2,3). Furthermore, intra-aortic balloon pump (IABP) does not provide significant advantage regarding survival in these patients (4). Thus, other strategies are needed in the life-threatening situation of progressive cardiogenic shock. Extra-corporal life support (ECLS) has been established several decades ago (5) and is used for transient stabilisation of the circulation or for bridging to transplantation (6). After canulation of the venous system, up to 6 litres of blood per minute are circulated and oxygenated via a turbine and reinfused into the femoral artery. Animal studies suggest that ventricular unloading reduces left ventricular wall stress und decreases myocardial infarct size (7). Here, we performed a retrospective study addressing the hypothesis that ECLS ª 2014 John Wiley & Sons Ltd Int J Clin Pract, April 2014, 68, 4, 529–531
might provide an option as bridge to recovery in patients with progressive cardiogenic shock after successful revascularisation. We hypothesised that intermittent ventricular unloading by ECLS therapy and paused or reduced application of catecholamines yields enhanced recovery of damaged myocardium. We conducted a retrospective study of all patients who have been treated with ECLS for cardiogenic shock because of acute myocardial ischaemia at our 19-bed single-centre cardiology intensive care unit from February 2012 to April 2013. During this time period, 12 patients were treated with ECLS (see Table 1). Inclusion criteria were progressive cardiogenic shock defined as persistent hypotension (systolic blood pressure < 90 mmHg in spite of cumulative catecholamine dosage exceeding 2.0 mg per hour) and successful PCI. Exclusion criteria were technical impossibility of ECLS implantation. ECLS implantation was performed in one case before PCI, in nine patients immediately after PCI in the catheterisation laboratory and in two patients 24 and 48 h after PCI with IABP bridging. ECLS implantation was performed under general anaesthesia by an interdisciplinary team consisting of cardiac surgeons, perfusionists and
cardiologists. Femoral artery and vein were used as cannula puncture sites. We compared the patients treated with ECLS to a control group, which comprised all consecutive patients with cardiogenic shock who were treated with catecholamines and IABP after PCI at our intensive care unit from January 2011 to January 2012. Outcome measures were survival 30 days after ECLS implantation and ECLS or IABP correlated complications. Comparisons between two groups concerning baseline characteristics were performed using the unpaired Student’s t-test or the Pearson’s chi-squared test. Data were defined statistically significant at a value of P < 0.05. The Kaplan– Meier method and Log Rank test were used for survival analysis. Data are expressed as mean standard deviation. Our analysis was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments. Since we performed a post hoc analysis, ethical approval or informed consent were not necessary. In the ECLS group, 10 patients were males (10 in the IABP group) and the mean age was 54.8 13.3 (68.3 12.2) years. All of them underwent successful percutaneous coronary revascularisation. Eight (10) patients
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