Influence of Dynamic and Static Obstructive Renal Artery on Early Prognosis in Stanford Type A Aortic Dissection

BACKGROUND

Acute kidney injury (AKI) after acute Stanford type A aortic dissection (STAAD) surgery has a high mortality rate. Clarifying what type of renal artery problem (dynamic obstructive renal artery, DORA, or static obstructive renal artery, SORA) secondary to STAAD benefits from true lumen opening is helpful in providing a reference for the indication of renal artery intervention.

METHODS

From May 2018 to December 2019, 292 acute STAAD patients who underwent aortic surgery were enrolled in this study. DORA, SORA, and renal malperfusion were diagnosed according to preoperative aortic enhanced computed tomography (CTA). Renal artery problems secondary to STAAD were divided into three types: type 1, normal renal artery; type 2, DORA; and type 3, SORA. Acute kidney injury was divided into three stages: Stage 1, Stage 2, and Stage 3, according to 2012 Kidney Disease: Improving Global Outcomes (KDIGO). The primary endpoint was all-cause 30-day in-hospital death, and the secondary endpoint was postoperative dialysis requirement. Univariate and multivariate analyses were performed to assess the difference among the three types.

RESULTS

Postoperative AKI occurred in 154 of 292 (52.7%) patients, and postoperative dialysis was present in 27 of 292 (9.2%) patients with STAAD. Postoperative AKI and dialysis were significantly more prevalent in the SORA group (AKI: 71% in SORA group vs 51.5% in DORA group vs 22.2% in normal group; postoperative dialysis: 22.2% in SORA group vs 5.4% in DORA group vs 6.1 in normal group). Thirty-day (30-day) mortality was also significantly higher in the SORA group (Log-rank test, p=0.012). Preoperative acute myocardial infarction and body mass index were the independent risk factors for 30-day mortality. Static obstructive renal artery, cardiopulmonary bypass time, and renal blood cell transfusion >3 units were the independent risk factors for postoperative dialysis requirement.

CONCLUSION

Static obstructive renal artery led to higher 30-day in-hospital mortality and more postoperative dialysis. Open surgery reduced renal ischaemia injury caused by DORA, but it could not reduce renal ischaemia injury caused by SORA.

Anterior mitral valve leaflet length in cats with hypertrophic cardiomyopathy

INTRODUCTION

Anterior mitral valve leaflet (AMVL) elongation is a recognised feature of hypertrophic cardiomyopathy (HCM). However, whether AMVL elongation precedes left ventricular hypertrophy in cats is currently unknown. The aim of this study was to explore the risk of developing an HCM phenotype in cats with an elongated AMVL.

ANIMALS

FIFTY-FIVE APPARENTLY HEALTHY CATS WITH A NORMAL BASELINE ECHOCARDIOGRAM AND A FOLLOW-UP ECHOCARDIOGRAM AT >ONE YEAR.

MATERIALS AND METHODS

This was a retrospective longitudinal study. Cats at the baseline were grouped based on whether or not they developed an HCM phenotype at follow-up. AMVL length and left atrial and left ventricular dimensions were measured from two-dimensional images.

RESULTS

The median follow-up period of the study population was 5.4 years (25th and 75th quartile, 2.7-6.7 years). During this time, 17 cats (30.9%) developed an HCM phenotype. At the baseline, cats that subsequently developed an HCM phenotype had greater AMVL length (9.4 mm [25th and 75th quartile, 9.0-10.6 mm] vs. 8.5 mm [25th and 75th quartile, 7.6-9.1 mm], P < 0.0001) and maximal left ventricular wall thickness (4.5 mm [25th and 75th quartile, 4.1-4.7 mm] vs. 4.0 mm [25th and 75th quartile, 3.7-4.6 mm], P = 0.007) than those that did not. Multiple logistic regression analysis confirmed that both baseline variables were independent predictors for development of an HCM phenotype.

CONCLUSIONS

The AMVL length was greater in cats that subsequently developed left ventricular hypertrophy. Further studies investigating the clinical application of AMVL in the natural history of feline HCM are warranted.

Relationship between Left Ventricular Outflow Tract Pressure Gradient and Hemoglobin in Patients with Hypertrophic Cardiomyopathy

BACKGROUND

Anemia caused by left ventricular outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM) has been reported, however, large clinical studies confirming this association are lacking. The objective of the present study was to investigate the relationship between left ventricular outflow tract (LVOT) pressure gradient and hemoglobin in patients with hypertrophic cardiomyopathy (HCM).

METHODS

Patient demographics, laboratory and echocardiography data from 310 patients diagnosed with HCM from our hospital who had undergone echocardiography from July 2014 to March 2019 were collected from medical records. Patients were classified into HOCM and non-HOCM groups.

RESULTS

Compared to the non-HOCM group, patients in the HOCM group had a lower hemoglobin level (112.2 ± 16.7 vs. 132.9 ± 22.2 g/L, p < 0.001). In addition, significant negative correlations between hemoglobin and LVOT pressure gradient were found in males (r = -0.568, p < 0.001) and females (r = -0.589, p < 0.001). Receiver operating characteristic curve analysis revealed that the best cut-off value for hemoglobin to predict HOCM in male patients was 128 g/L with 74.19% sensitivity and 75.51% specificity (area under the curve: 0.763, p < 0.001). For female patients, the cut-off value was 125 g/L, with a sensitivity and specificity of 89.39% and 48.48%, respectively (area under the curve: 0.718, p < 0.001).

CONCLUSIONS

Our results indicate that hemoglobin level is inversely proportional to the LVOT gradient pressure and has value for predicting outflow tract obstruction in patients with HCM.

Complete post-operative resolution of "temporary" end-stage kidney disease secondary to aortic dissection without static renal artery obstruction: a case study

BACKGROUND

Acute kidney injury (AKI), which may progress to end-stage kidney disease (ESKD), is a potential complication of aortic dissection. Notably, in all reported ESKD cases secondary to aortic dissection, imaging evidence of static obstruction of the renal arteries always shows either renal artery stenosis or extension of the dissection into the renal arteries.

CASE PRESENTATION

We present the case of a 58-year-old man with hypertension who was diagnosed with a Stanford type B aortic dissection and treated with medications alone because there were no obvious findings indicative of dissection involving the renal arteries. He had AKI, which unexpectedly progressed to ESKD, without any radiological evidence of direct involvement of the renal arteries. Thus, we failed to attribute the ESKD to the dissection and hesitated to perform any surgical intervention. Nevertheless, the patient's hormonal levels, fractional excretion values, ankle brachial indices, and Doppler resistive indices seemed to indirectly suggest kidney malperfusion and implied renal artery hypo-perfusion. However, abdominal computed tomography imaging only revealed progressive thrombotic obstruction of the false lumen and compression of the true lumen in the descending thoracic aorta, despite the absence of anatomical blockage of renal artery perfusion. Later, signs of peripheral malperfusion, such as intermittent claudication, necessitated surgical intervention; a graft replacement of the aorta was performed. Post-operatively, the patient completely recovered after 3 months of haemodialysis, and the markers that had pre-operatively suggested decreased renal bloodstream normalised with recovery of kidney function.

CONCLUSIONS

To the best of our knowledge, this is the first report of severe AKI, secondary to aortic dissection, without direct renal artery obstruction, which progressed to "temporary" ESKD and was resolved following surgery. This case suggests that only coarctation above the renal artery branches following an aortic dissection can progress AKI to ESKD, despite the absence of radiological evidence confirming an obvious anatomical blockage. Further, indirect markers suggestive of decreased renal blood flow, such as ankle brachial indices, renal artery resistive indices, urinary excretion fractions, and hormonal changes, are useful for evaluating concomitant AKI and may indicate the need for surgical intervention after a Stanford type B aortic dissection.

Dynamic right ventricular outflow obstruction: A rare cause of hypotension during anestesia induction

INTRODUCTION

Dynamic obstruction of right ventricle outflow tract (RVOTO) is a rare condition that may acutely cause severe heart failure. It has been reported in some hypertrophic cardiomyopathies, after lung transplantation, and in some cases of hemodynamic instability after cardiopulmonary bypass.

PRESENTATION OF CASE

We report the case of a 71-year-old man who developed severe hypotension during the induction of general anesthesia for surgical coronary revascularization. Hypotension did not respond to the initial treatment with vasoconstrictors and fluids. RVOTO was suspected during pulmonary artery catheterization because of the difficulty of the catheter tip to move from the right ventricle to the pulmonary artery and, successively, because of the finding of a large gradient between the systolic pressure in the right ventricle and in the pulmonary artery. The diagnosis was confirmed by transesophageal echocardiogram (TEE). Hemodynamics recovered after the infusion of cristalloids, 1L, and the suspension of vasoconstrictors and inotropes.

DISCUSSION

This is the first case in which RVOTO was observed during the induction of general anesthesia. Although this is a rare condition, the diagnostic suspect is of outmost importance because treatment is mainly based on fluid administration, and drugs with positive inotropic properties (like most vasoconstrictors) are contraindicated.

CONCLUSIONS

RVOTO is an unusual, but possible cause of severe arterial hypotension during general anesthesia induction. TEE is useful for the evaluation of severely hypotensive patients who do not respond to routine treatment with fluids and vasoconstrictors.

Paradoxical heart failure precipitated by profound dehydration: intraventricular dynamic obstruction and significant mitral regurgitation in a volume-depleted heart

Occurrence of dynamic left ventricular outflow tract (LVOT) obstruction is not infrequent in critically ill patients, and it is associated with potential danger. Here, we report a case of transient heart failure with hemodynamic deterioration paradoxically induced by extreme dehydration. This article describes clinical features of the patient and echocardiographic findings of dynamic LVOT obstruction and significant mitral regurgitation caused by systolic anterior motion of the mitral valve in a volume-depleted heart.