Cardiogenic shock (CS) continues to show elevated mortality.1 The only available treatment with clear clinical efficacy is early revascularization of patients with CS after acute myocardial infarction (AMI).2 However, in recent years there has been an exponential increase in the use of mechanical circulatory support (MCS) devices for highly severe patients who are refractory to medical therapy, who have a mortality rate of almost 100%.3,4 These devices have 2 main objectives: a) to support the functioning and recovery of the affected ventricles; and b) to ensure adequate perfusion and oxygenation of vital organs to avoid multiple organ failure and death.

The use of these and other complex therapies in refractory patients with CS supports the creation of multidisciplinary teams specialized in its management. These teams, primarily comprising advanced heart failure (HF) cardiologists, interventional cardiologists, cardiac surgeons, and critical care specialists, are integrated into hospitals with the specialized focus and resources to manage patients with CS.5,6 In addition to their internal coordination, they are designed to act as referral centers for a hierarchical network of hospitals with different care levels, analogous to those used for AMI and stroke, which can provide better coverage of the referral population of an area.7 Similar experiences in other countries and contexts have achieved satisfactory results.4,8,9

The objective of the present study was to analyze the initial outcomes of a care program for patients with CS, mainly refractory CS, after the creation of a multidisciplinary team in our hospital and coordination with a network of hospitals in our referral region.

In total, the “shock code” was activated in 152 patients (153 events; 1 patient had 2 CS processes but only the first was considered). Of these, 69 were local patients and 83 were telephone consultations from other hospitals. Finally, of these 83 patients, 61 were transferred to our center. The main reasons for not transferring patients were a possible adequate and agreed treatment in the hospital treating the patient (n=13) and futility (n=6). A total of 130 patients (69 local and 61 transferred) were treated and included in the present analysis (figure 2).

Figure 2.

Flow chart of patients included in the program. AMI, acute myocardial infarction; CS, cardiogenic shock; HTx, heart transplantation; LT-VAD, longterm ventricular assist device; MCS, mechanical circulatory support; MOF, multiple organ failure; PGF, primary graft failure; ST-VAD, short-term ventricular assist device; VA-ECMO, venoarterial extracorporeal membrane oxygenation.

(0.25MB).

The patients’ demographic characteristics are reported in table 1. The mean patient age was 52±15 years (72% were men). The predominant causes of the CS were acute decompensated HF (29%), AMI (26%), and postcardiotomy CS (25%). The causes differed between local and transferred patients: more than half of local patients had postoperative CS (postcardiotomy and after primary graft failure), whereas transferred patients tended to have AMI and acute decompensated HF.

Transferred patients were mainly referred from level II hospitals (69%) and from within the autonomous community itself (59%). The median time from CS diagnosis to transfer was 2 [1-4] days. Eighteen patients were transferred with an IABP, 14 with VA-ECMO (10 of the 11 patients with peripheral cannulation also had an IABP), and 6 with ST-VAD (all with Levitronix CentriMag). No notable complications were recorded during the transfer (figure 3).

Figure 3.

Distribution of patients referred and transferred to the referral hospital. ACs, autonomous communities; CVS, cardiovascular surgery; ICU, intensive care unit.

(0.23MB).

The patients’ clinical situation at admission and in the first 24hours in our intensive care unit is described in table 2 and table 3; 41 patients (32%) had previously experienced a cardiopulmonary arrest and 80 (62%) had an INTERMACS profile of 1. The lactate, creatinine, aspartate aminotransferase, and alanine aminotransferase levels and SOFA, SAPS II, and APACHE II scores reflect the multiple organ failure experienced by the patients in the first hours of admission to our center. At 24hours, 63% of the patients needed 2 or more vasoactive drugs to maintain hemodynamic stability. Transferred patients had lower lactate levels at admission (5.5 [2.9-12.3] vs 2.0 [1.2-4.8] mmol/L; P=.001) but higher transaminase levels (aspartate aminotransferase, 100 [48-304] vs 292 [49-820] mg/dL; P=.049; alanine aminotransferase, 55 [22-134] vs 167 [36-896] mg/dL; P=.003) (table 3).

An MCS device was used in 105 of the 130 patients (81%). Escalation of support from the IABP was required in 57% of these patients. Only 10 patients (8% of the series) did not receive an IABP or MCS device. VA-ECMO was the first device used in more than half of the patients (61 of 105; 58%). The first device was the Levitronix CentriMag in 30 patients (8 left ventricular, 2 right ventricular, and 20 biventricular) and the Impella CP in 14. In 17 patients, a second MCS device was used to stabilize the patient, mainly due to respiratory and hemodynamic problems in patients with a peripheral VA-ECMO as a bridge to a Levitronix CentriMag ST-VAD (table 4).

In total, 78 patients (60%) survived the acute phase: 42 achieved myocardial recovery, 33 underwent an urgent transplant, and 3 received an EXCOR ST-VAD as a “bridge to transplant”. The overall survival to discharge rate was 57% (74 of 130 patients; 51% for local patients and 64% for transferred patients). Among the patients who survived the acute CS phase, the survival to discharge rate was 95% (74 of 78 patients). Only 1 patient died of arrhythmic storm after recovery and 3 after HTx (primary graft failure, ischemic stroke, and sepsis). The survival to discharge rate after urgent HTx in this series was 91% (30 of 33 patients). The 3 patients with an EXCOR LT-VAD underwent HTx 85, 90, and 140 days after the implantation. In Kaplan-Meier analysis, the 1-year survival rate of the entire cohort was 53%. In the survivors, after a median follow-up of 221 [44-699] days after discharge, there were only 5 deaths, with a 1-year actuarial survival of 94%, without differences according to patient destination (figure 4).

Figure 4.

A: actuarial Kaplan-Meier survival curve for the entire series. B: actuarial Kaplan-Meier survival curve for patients who survived to discharge according to destination. 95%CI, 95% confidence interval; HTx, heart transplantation; LT-VAD, long-term ventricular assist device.

(0.13MB).

The results of univariable and multivariable analyses of in-hospital mortality are reported in table 5. Independent predictors of in-hospital mortality were CS after AMI (odds ratio [OR]=3.35; 95% confidence interval [95%CI], 1.21-9.24; P=.02), the initial lactate level (OR=1.13; 95%CI, 1.05-1.22; P=.002), the SAPS II score in the first 24hours (OR=1.06; 95%CI, 1.03-1.1; P=.001), and the VIS at 24hours after admission (OR=1.1; 95%CI, 1.01-1.2; P=.037). The C statistic of the multivariable model that included the clinical parameters from the first hours of admission was 0.82 (95%CI, 0.75-0.90).

The main causes of death during the acute CS phase were multiple organ failure in 29 of the 52 patients who died (56%), neurological damage in 12 (23%; 8 anoxic encephalopathies, 2 ischemic strokes, and 2 hemorrhagic strokes), and sepsis in 5 (10%). Of the 105 patients with MCS, 76 (72%) had at least 1 related complication. The main complications were bleeding requiring transfusion or reintervention in 47 patients (45%) and stroke in 13 (12%; 9 ischemic and 4 hemorrhagic), as well as peripheral arterial disease related to an MCS device in 9 patients (9%). Just 2 of the 13 patients with stroke and 3 of the 9 with peripheral arterial disease survived to hospital discharge.

This work shows the outcomes of a care program for patients with CS, mainly refractory CS, after the creation of a multidisciplinary team for CS and the organization of a network comprising regional hospitals. The main findings are that a) 57% of patients survived to discharge; b) patient survival was mainly due to myocardial recovery or urgent HTx; c) CS cause, lactate level, SAPS II score, and VIS were independent predictors of in-hospital mortality; and d) patients who survived to discharge had excellent mid-term survival (94% at 1 year).

In recent years, there has been a surge of interest in improving the management of patients with CS. In addition to an increased use of MCS devices,3 a large part of the effort has been focused on organizational aspects, with the creation of experienced multidisciplinary teams and hospital networks for patient transfer to referral centers.5–7 These networks permit a) better and more homogeneous care of all patients in a specific region; b) centralized activity, increased team experience, and, accordingly, improved outcomes for this condition; and c) a care headquarters that enables the generation of the scientific evidence lacking in this field. As far as we know, this series is the first reported from Spain with this organizational model and also has unique characteristics vs other published series.

First, the results were obtained from a strategy based on a priori defined selection criteria, in contrast to other series that have been built around the use of MCS devices or the patients’ severity profile. Although this may increase the heterogeneity of the studied population, we believe that it has the virtue of showing the “real life” activity and the possibilities of a program with these characteristics. The activity and outcome data could be useful for the planning of other teams in other regions. During the study period, an average of 2 to 3 patients were treated per month and the outcomes have been stable, possibly due to the educational and training activities of the team in the years prior to program initiation. Despite the difficulty of comparing the distinct CS series published, the survival to discharge rate reported in our work is in line with those of other groups with similar programs (table 6).4,8,9 Although it might appear that no advances have been made in the prognosis of these patients in recent decades, given that their mortality is still around 50%, we believe that the characteristics of the patients treated in our center and others reflect an increasingly less healthy population that would previously not have had any other treatment options.

Second, and this point is related to the first, this program included all causes of CS, with no exclusion criteria. Although the patients’ pathophysiology and clinical context are distinct, particularly in the postoperative patients, CS patients’ treatment and destination are often the same. In our series, 74% of the patients included had CS that was not secondary to AMI. These activity data, with less than one third of all patients having CS after AMI, are in line with those of other recent publications, highlighting the change in the profile of CS patients now treated in intensive care units.12

Finally, in this series, urgent HTx was the destination of 42% of the patients who survived the acute CS phase because they showed no signs of myocardial recovery. This elevated use of HTx in patients with CS is possible only in countries with a high rate of donations and with relatively short waiting periods, such as ours.13 Although the HTx outcomes in this type of patient can be inferior to those obtained with elective HTx, which has been an object of study and source of controversy,14,15 centers with experience and with adequate selection of recipients after the resolution of multiple organ failure can achieve> 90% survival to discharge rates, as in our series (30 of 33 patients, 91%).

SAPS II score, CS after AMI, lactate level at admission, and IVS were powerful independent predictors of in-hospital mortality in our series. These findings are in line with the available evidence. The SAPS II score, which includes patients’ age, blood pressure, heart rate, Glasgow Coma Scale, and other biochemical and respiratory variables, has already been shown to have predictive value for CS patients’ mortality.4,16 In addition, CS after AMI and lactate level have been correlated with poor prognosis in these patients.4,17 Finally, Na et al.18 recently demonstrated that an elevated VIS in the first 48hours after CS diagnosis is associated with higher in-hospital mortality, as seen in this study.

The creation of multidisciplinary teams for the management of patients with CS, predominantly refractory CS, and coordination with a network of hospitals in a specific region are feasible and achieve survival to discharge in more than half of patients treated. In Spain, most of the patients survive due to myocardial recovery or urgent HTx. These outcomes, together with other published experiences, support the application of this internal and regional organizational model to all geographic regions. Multicenter and larger studies are required to better determine the benefits of this strategy and improve outcomes.

The present work has been partially funded by a grant awarded by the Spanish Society of Cardiology for “Proyectos de investigación SEC-ROVI para promoción de la investigación en insuficiencia cardiaca de la Sección de Insuficiencia Cardiaca 2017” (“SEC-ROVI research projects for the promotion of research into heart failure of the Heart Failure Section 2017”).

None.