|Year : 2019 | Volume
| Issue : 4 | Page : 424-428
Dynamic left intraventricular obstruction in patients with septic shock: pathogenetic role and prognostic implications
Samir Elhadidy, Moustafa Rafea, Suzy Fawzy, Abdo Elazab
Critical Care Medicine Department, Cairo University, Giza, Egypt
|Date of Submission||21-Apr-2019|
|Date of Acceptance||18-Jun-2019|
|Date of Web Publication||06-Jan-2020|
Lecturer of Critical Care Medicine Department, Cairo University
Source of Support: None, Conflict of Interest: None
Background Left intraventricular flow obstruction (IVO) has been classically described in asymmetric hypertrophic cardiomyopathy, usually at the level of the left ventricular outflow tract (LVOT) or at midcavitary level, which is due to systolic anterior movement of the anterior leaflet of the mitral valve. This phenomenon has also been previously described in certain clinical situations mainly revolving around hypovolemia and catecholamine exposure and recently as a frequent event in patients with septic shock with an important correlation with fluid responsiveness. Multiple studies have demonstrated that static parameters limited the predictive value for fluid responsiveness, whereas dynamic parameters have shown a greater clinical use, including respiratory changes in aortic blood velocity, superior vena cava collapsibility, inferior vena cava (IVC) collapsibility, and changes in stroke volume and Cardiac Output (CO) owing to passive leg raising.
Objective This study aimed to assess (a) the prevalence of dynamic IVO in patients with septic shock; (b) relation among IVO, volume status, and fluid responsiveness; and (c) relation between IVO and in-hospital mortality.
Patients and methods A total of 40 patients with septic shock were studied over a period of 1 year for the presence of Doppler signs of dynamic IVO, clinical characteristics, hemodynamic parameters, and APACHE II and SOFA scoring. Echocardiographic data including IVC collapsibility, CO, LVOT mean and peak pressure gradient, LVOT maximum velocity, and midcavitary Doppler pattern were recorded initially and following fluid resuscitation (30 ml/kg). Patients were categorized into two groups: group A included patients with IVO and group B included patients without IVO. There was a statistically nonsignificant difference between both groups regarding the baseline demographic, clinical, and hemodynamic parameters.
Results A total of 40 (45% were males and 55% females) patients, with a mean age of 52±20 years, were studied, of whom a total of 13 (32%) had IVO versus 27 patients without IVO. Following fluid infusion, as compared with group B, group A showed significantly greater increase in Cardiac Output (COP) (5.85±1.4 vs. 4.4±1.8, P=0.0203) and IVC collapsibility (54.42±6.8 vs 50.56±13, P=0.42). ICU mortality was significantly higher in patients with IVO [10/13 (76.9%)] versus patients without IVO [7/27 (25.9%), P<0.002].
Conclusion Dynamic left IVO is not uncommon in patients with septic shock in ICU. Response to fluid infusion was significantly higher in patients with IVO compared with patients without IVO, pointing to an additional role of fluid resuscitation in patients with sepsis.
Keywords: intraventricular obstruction, left ventricular outflow tract, systolic anterior movement
|How to cite this article:|
Elhadidy S, Rafea M, Fawzy S, Elazab A. Dynamic left intraventricular obstruction in patients with septic shock: pathogenetic role and prognostic implications. Res Opin Anesth Intensive Care 2019;6:424-8
|How to cite this URL:|
Elhadidy S, Rafea M, Fawzy S, Elazab A. Dynamic left intraventricular obstruction in patients with septic shock: pathogenetic role and prognostic implications. Res Opin Anesth Intensive Care [serial online] 2019 [cited 2020 Jan 29];6:424-8. Available from: http://www.roaic.eg.net/text.asp?2019/6/4/424/275138
| Introduction|| |
It is well known that hypertrophic obstructive cardiomyopathy is the most frequently reported cause of the dynamic left ventricular outflow tract (LVOT) obstruction. Moreover, a hyperdynamic state as a result of catecholamine therapy  has been linked to this condition. Dynamic LVOT obstruction has been reported during dobutamine stress echocardiography, but most of these cases did not show any significant clinical or hemodynamic changes . A few cases have described a catecholamine-induced dynamic LVOT obstruction compromised by hemodynamic deterioration in a structurally normal heart . Treatment with inotropic agents in patients experiencing shock symptoms remains a common practice and mandatory mainstay in the field of medicine. The mechanisms behind the catecholamine-induced deterioration may include ischemic left ventricular dysfunction, the vasodilatation effect of dobutamine, tachycardia, and the dynamic LVOT obstruction resulting from a hypercontractile state in relative hypovolemia .
The data showed an association between the presence of this obstructive flow pattern on LV Doppler flow and the presence of hypovolemia and cardiac hypercontractility, and also demonstrated that these patients frequently present with small and pseudohypertrophic left ventricles. The presence of intraventricular obstruction (IVO) is associated with a high mortality rate.
| Patients and methods|| |
Over a period of 1 year starting from April 2016 to march 2017, 40 (18 males and 22 females) consecutive patients who presented to the Critical Care Department, Cairo University Hospitals, with septic shock were included in our study. We excluded patients with hypertrophic obstructive cardiomyopathy, pulmonary edema, valvular heart disease, arrhythmias, mechanically ventilated patients, conditions that raise intra-abdominal pressure, and poor echocardiographic window.
All patients were subjected to the following:
- Full clinical history and detailed general and local clinical examinations; APACHE II and SOFA scoring; routine laboratory tests, including Complete blood picture (CBC), liver profile (Alanine transaminase (ALT), Alanine aspartate transaminase (AST), and bilirubin), renal functions (urea and creatinine), serum blood glucose, and arterial blood gases. Hemoglobin level was frequently checked on daily basis to ensure adequate oxygen delivery with the augmentation of cardiac output.
Fluid resuscitation was done through administration of fluid challenge with 30 ml/kg of crystalloid solution.
Echocardiographic study with assessment of the following:
- Inferior vena cava (IVC) collapsibility index:
- The maximum and minimum IVC diameters were calculated by tracking the distance between anterior and posterior walls in M mode. The IVC collapsibility index was calculated using the following formula:
- Cardiac output:
- It was calculated by the following equation:
- LVOT was measured from the parasternal long axis view by M mode, and LVOT velocity time index was measured using pulsed Doppler at the level of the LVOT, from an apical five-chamber view.
- LVOT and mid-cavitary flow Doppler pattern:
- Using pulsed wave Doppler from an apical five-chamber view, Left ventricular (LV) outflow Doppler data [velocity and mean and peak pressure gradient (PG)] and mid-cavitary flow Doppler pattern (velocity and mean PG) were recorded.
- Peak velocity on LVOT or mid-cavitary at least 0.9 m/s suggests IVO.
All echocardiographic readings were recorded on admission to the ICU before fluid resuscitation and then after fluid resuscitation. All readings were recorded at the end of expiration and averaged over several consecutive beats.
Patients were categorized according to the presence of dynamic IVO into two groups: patients with dynamic left IVO and patients without dynamic IVO, and both groups were compared regarding volume status, fluid responsiveness, echocardiographic findings, and in-hospital mortality.
Data were coded and entered using the statistical package statistical package for the social sciences (SPSS) version 24 (Critical Care Medicine Department, Cairo University Kasr El Aini Medical School-Egypt, Cairo). Data was summarized using mean, SD, median, minimum and maximum in quantitative data and using frequency (count) and relative frequency (percentage) for categorical data. Comparisons between quantitative variables were done using the nonparametric Mann–Whitney test. For comparison of serial measurements within each patient, the nonparametric Wilcoxon signed rank test was used . For comparing categorical data, χ2-test was performed. Exact test was used instead when the expected frequency is less than 5. P values less than 0.05 were considered as statistically significant .
| Results|| |
This prospective study included 40 [18 (45%) males and 22 (55%) females] patients, with mean age of 52±20 years. They were divided into two groups:
- Group A included patients with IVO.
- Group B included patients without IVO.
There was no statistically significant difference between both study groups regarding mean age (P=0.9), sex (P=0.435), and comorbid conditions, as mentioned and illustrated in [Table 1] and [Table 2].
Source of sepsis
The cause of sepsis was divided among pneumonia (25 patients), intra-abdominal sepsis (10 patients), urinary tract infection (four patients), and soft tissue infection (one patient). There was no statistically significant difference between both groups regarding the cause of sepsis ([Table 3]).
Hemodynamic characteristics of the patients
There was no statistically significant difference between both groups regarding hemodynamic parameters, as shown in [Table 4].
SOFA and APACHE II scoring of the studied patients
SOFA scoring and APACHE II scoring ([Table 5]) were statistically higher in the group I than group II (P=0.001 and 0.021, respectively).
Echocardiographic data of both groups
All echocardiographic parameters before fluid resuscitation are shown in [Table 6] and following fluid resuscitation are shown in [Table 7].
|Table 7 Echocardiographic data of both groups before fluid resuscitation|
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There was a statistically significant difference between both groups regarding LVOT velocity time index, LVOT mean PG, LVOT peak PG, LVOT Vmax, and mid cavitary mean PG (P<0.001).
Echocardiographic study revealed that 13 of the 40 patients studied (representing 32.5%) had dynamic IVO, of whom two patients had mid LV obstruction and 11 patients had LVOT obstruction, and 27 (67.5%) patients were without IVO.
Comparison of IVO gradient before and after a single 30 ml/kg fluid bolus revealed that the difference before and after volume expansion was statistically significant (P=0.001), as shown in [Figure 1].
|Figure 1 Intraventricular obstruction gradient before and after fluid bolus.|
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Fluid responsiveness of the studied patients
Patients were considered fluid responsive if they had an increase in cardiac output after volume infusion and IVC collapsibility was more than 50%.
Twenty-eight (70%) patients of all studied patients (40 patients) were fluid responsive: 11 (84.6%) patients in group I and 17 (63%) patients in group II ([Table 7] and [Table 8]).
There was no significant difference between both groups regarding the incidence of fluid responsiveness (P=0.271), as shown in [Table 9].
ICU stay and ICU
There was no statistically significant difference between both groups as regarding the duration of ICU stay ([Table 9]), with P value 0.217.
ICU mortality ([Table 10]) was statistically higher in group I [10/13 (76.9%)] versus in group II [7/27 (25.9%)] (P<0.002).
| Discussion|| |
In this study, we found no relation between IVO and age, sex, or any of the comorbidities found in studied patients and source of sepsis. Such finding was also stated in the study conducted by Chauvet et al. .
Incidence of IVO in our study was 32%. This was similar to the results of Chauvet et al. , who conducted a study on 218 patients with septic shock of whom 47 (22%) patients had a documented IVO flow pattern .
In concordance with our study was the study by Caselli et al. , which showed that LVOT obstruction is not a rare problem in the intensive care units and can precipitate hemodynamic shock unresponsive to catecholamine therapy. Hypovolemia, catecholamine infusion, and mechanical ventilation induce geometric modification of the left ventricle that causes a systolic anterior motion of the anterior mitral leaflet and a severe subaortic gradient. Simple restoration of fluids and discontinuation of medical therapy changed the outcome of the patient .
In agreement with our study, Yang et al.  reported a case of a patient with a structurally normal heart who developed hemodynamic deterioration owing to severe LVOT obstruction following treatment with catecholamines and also reported that hypovolemia accompanied with a hyperdynamic condition, resulting from catecholamine treatment, had caused dynamic LVOT obstruction owing to the systolic anterior motion of the mitral valve leaflet, and finally reported that the solution for this is early recognition and correction of aggravating factors such as withdrawal of catecholamine therapy and volume replacement .
Hence, all patients at risk for developing hypovolemia, a narrowing of the LVOT, a small LV lumen, tachycardia, LV hyperkinesia, or exposure to catecholamine use may develop IVO.
The treatment instituted in sepsis also adds risk factors: vasopressors used on hypovolemic patients and inotropes both contribute to the hypercontractility, and the frequent use of loop diuretics and sometimes even β-agonists for the treatment of respiratory distress, are all contributing factors to the development of IVO gradients .
In this study, we used two scores (SOFA and APACHE scores) to assess severity and were statistically higher in the group of patients with septic shock with LV obstruction when compared with patients without obstruction (P=0.001 and 0.021, respectively). Similar to our results, Chauvet et al.  used APACHE II score and was statistically higher in the group of patients with septic shock with IVO (P=0.001).
Our results revealed higher incidence of fluid responsiveness in patients who had IVO but without statistically significant difference.
Similar to our study, Chauvet et al. , conducted a study on 218 patients with septic shock of whom 47 patients had IVO and proved that patients with IVO were fluid responsive. Of the 47 patients, 35 (79%) had an increase of at least 12% in cardiac output.
The fact that the fluid responsiveness observed in patients with IVO was close to 79% as conducted by, Chauvet et al. , constitutes good evidence for performing a fluid challenge on patients with septic shock with this echocardiographic finding. This finding suggests that the presence of an IVO in a hypotensive septic patient is likely to signify quite severe hypovolemia. Understanding this may be crucial to adequate patient management and to prevent further fluid depletion and catecholamine administration in these patients owing to a misinterpretation of their hemodynamic and cardiac status.In our study, ICU mortality was also statistically higher in the group of patients with septic shock with LV obstruction when compared with patients without obstruction [10/13 (76.9%) vs. 7/27 (25.9%), P<0.002].
In agreement of our study, Chauvet et al. , showed that ICU mortality was statistically higher in the group of patients with septic shock with LV obstruction when compared with patients without obstruction [25/47 (53%) vs. 41/171 (24%), P<0.01].
| Conclusion|| |
- Dynamic left IVO in the early phase of septic shock is not rare.
- The high degree of fluid responsiveness noted in these patients justifies considering a fluid challenge for patients with septic shock with IVO as well as parsimony in the administration of inotropic amines and diuretics.
- The presence of dynamic IVO is associated with a high mortality rate.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]