Renal Frame Count and Renal Blush Grade

Can wound blush be used as an indicator for termination of endovascular procedures in chronic limb-threatening ischemia patients?

INTRODUCTION

Predicting the outcomes of endovascular revascularization of chronic limb-threatening ischemia (CLTI) patients with foot wounds can be challenging. Angiographic wound blush (WB) assessment has been found to be a helpful tool to assess wound perfusion. The aim of this study is to evaluate WB during endovascular revascularization of CLTI patients and its effects on treatment outcomes.

METHODS

This prospective study included all CLTI patients with foot wounds who underwent successful endovascular revascularization of infrainguinal arterial disease between 2019 and 2021. Patients were grouped according to the WB status into positive WB (group A) and negative WB (group B). Both groups were compared for demographics, comorbidities, clinical picture, and 12-month limb-based patency (LBP) and amputation-free survival (AFS) rates.

RESULTS

The study included 69 patients of Rutherford classes 5 (46.4%) and 6 (53.6%), with the main arterial lesion located at the femoropopliteal (58%) or infrapopliteal (42%) segments. Completion angiography showed positive WB in 38 (55.1%) patients and negative WB in 31 (44.9%) patients. Both groups were comparable regarding patient presentation, site of the main arterial lesion, and distribution of foot lesions in relation to the feeding artery. The overall 12-month LBP and AFS rates were 21.7% and 39.1%, respectively, with significantly better rates in group A than in group B (LBP, 31.6% vs 9.7%, p = 0.001 and AFS, 54.1% vs 22.2%, p = 0.006, respectively). Successful angiosome-based direct flow to the foot was achieved in 38 patients (55.1%), resulting in significantly better 12-month AFS rates than those with indirect revascularization (54.8% vs 26.3%, p = 0.036, respectively), despite the comparable 12-LBP rates between the direct and indirect revascularization groups (29% vs 15.8%, p = 0.133, respectively). Multivariate logistic regression analysis identified smoking as a significant predictor of a major amputation, whereas positive WB and successful direct revascularization were significant predictors of limb salvage.

CONCLUSIONS

WB can serve as a predictor for AFS and LBP during endovascular revascularization of CLTI patients with foot wounds. A positive WB may guide the decision to conclude an endovascular procedure, potentially avoiding unnecessary complicated maneuvers to recanalize more vessels. Conversely, a negative WB may suggest the need for further revascularization attempts to augment wound perfusion and healing.

Renal perfusion improvement in the perioperative period after unilateral endovascular revascularization in patients with atherosclerotic renal artery stenosis

Background

The clinical benefits of endovascular treatment in renal artery stenosis (RAS) remain controversial. This study used an intraoperative renal perfusion imaging technique, called flat-panel detector parenchymal blood volume imaging (FD-PBV), to observe the change in renal perfusion after endovascular treatment in RAS.

Materials and methods

In a prospective, single-center study, we assigned 30 patients with atherosclerotic RAS who underwent endovascular treatment between March 2016 and March 2021. The preoperative and postoperative results of renal perfusion, blood pressure, and renal function, were compared.

Results

Both median kidney volume (p < 0.001) and median preoperative mean density of contrast medium (MDCM) (p = 0.028) increased significantly after endovascular treatment. The ratio of postoperative and preoperative MDCM differed greatly among the patients. For patients with preoperative MDCM <304.0 HU (Subgroup A, 15 cases), MDCM significantly increased after treatment (p = 0.001) and 12 (80.0%) patients had more than 10% increase in renal perfusion. For patients who had relatively high preoperative renal perfusion (MDCM ≥304.0 HU, Subgroup B, 15 cases), preoperative and postoperative MDCM were similar (p = 0.776). On the other hand, the serum creatinine levels significantly decreased in Subgroup A (p = 0.033) and fewer antihypertensive drugs were used after endovascular revascularization (p = 0.041). The preoperative and postoperative creatinine levels and number of antihypertensive drugs were similar in Subgroup B.

Conclusions

During the perioperative period, RAS patients with relatively low preoperative renal perfusion levels had greater improvement in renal perfusion, renal function, and blood pressure control after endovascular treatment. The improvement of renal function needs to be confirmed by long-term follow-up.

Correlation of renal cortical blood perfusion and BP response after renal artery stenting

Background

This study aimed to observe the correlation between renal cortical blood perfusion (CBP) parameters and BP response in patients with severe renal artery stenosis (RAS) who underwent stenting.

Methods

This was a single-center retrospective cohort study. A total of 164 patients with unilateral severe RAS after successful percutaneous transluminal renal artery stenting in Beijing Hospital from October 2017 to December 2020 were included. According to the results of BP evaluated at 12 months, all patients were divided into the BP response group (n = 98) and BP nonresponse group (n = 66). The baseline clinical and imaging characteristics and follow-up data about 24 h ABPM and CBP were recorded and analyzed. Pearson correlation analysis was used to evaluate the relationship between CBP parameters and 24 h average SBP. Univariate and multivariate logistic regression analysis was used to evaluate the risk factors for BP response.

Results

Among 164 patients with severe RAS, there were 100 males (61.0%), aged 37–75 years, with an average of 56.8 ± 18.4 years, and average artery stenosis of 84.0 ± 12.5%. The BP nonresponse patients had a longer duration of hypertension, more current smoking subjects and diabetic patients, lower eGFR, increased number of hypertensive agents, and rate of insulin compared with the BP response group (P < 0.05). After PTRAS, patients in the BP response group were associated with significantly lower BP and improved CPB, characterized by increased levels of maximum intensity (IMAX), area under ascending curve (AUC1), area under the descending curve (AUC2), shortened rising time (RT), mean transit time (mTT), and prolonged time to peak intensity (TTP; P < 0.05). However, the BP nonresponse group was only associated with significantly reduced RT (P < 0.05) compared with baseline data. During an average follow-up of 11.5 ± 1.7 months, the BP response group was associated with significantly lower levels of SBP, DBP, 24 h average SBP, and 24 h average DBP compared with the nonresponse group (P < 0.05). Pearson correlation analysis showed that the the pre-operative CBP parameters, including IMAX (r = 0.317), RT (r = 0.249), AUC1 (r = 0.614), AUC2 (r = 0.558), and postoperative CBP parameters, including RT (r = 0.283), AUC1 (r = 0.659), and AUC2 (r = 0.674) were significantly positively correlated with the 24 h average SBP, while the postoperative TTP (r = −0.413) and mTT (r = −0.472) were negatively correlated with 24 h average SBP (P < 0.05). Multivariate Logistic regression analysis found that diabetes (OR = 1.294), NT-proBNP (OR = 1.395), number of antihypertensive agents (OR = 2.135), pre-operation IMAX (OR = 1.534), post-operation AUC2 (OR = 2.417), and baseline dDBP (OR = 2.038) were related factors for BP response (all P < 0.05).

Conclusion

Patients in the BP nonresponse group often have diabetes, a longer duration of hypertension, significantly reduced glomerular filtration rate, and heavier renal artery stenosis. CBP parameters are closely related to 24 h average SBP, and pre-operation IMAX and post-operation AUC2 are markers for a positive BP response.

The spectrum and systemic associations of microvascular dysfunction in the heart and other organs

Microvascular dysfunction (MVD) contributes to several conditions that increase morbidity and mortality, including ischemic heart disease, heart failure, dementia, chronic kidney disease and hypertension. Consequently, MVD imposes a substantial burden on healthcare systems worldwide. In comparison to macrovascular dysfunction, MVD has been incompletely investigated, and it remains uncertain whether MVD in an organ constitutes a distinct pathology or a manifestation of a systemic disorder. Here, we summarize and appraise the techniques that are used to diagnose MVD. We review the disorders of the heart, brain and kidneys in which the role of MVD has been highlighted and summarize evidence hinting at a systemic or multi-organ nature of MVD. Finally, we discuss the benefits and limitations of implementing MVD testing in clinical practice with a focus on new interventions that are beginning to emerge.

When and How Should We Revascularize Patients With Atherosclerotic Renal Artery Stenosis?

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension and may lead to resistant (refractory) hypertension, progressive decline in renal function, and cardiac destabilization syndromes (pulmonary edema, recurrent heart failure, or acute coronary syndromes) despite guideline-directed medical therapy. Although randomized controlled trials comparing medical therapy with medical therapy and renal artery stenting have failed to show a benefit for renal artery stenting, according to comparative effectiveness reviews by the Agency for Healthcare Research and Quality, the trials may not have enrolled patients with the most severe atherosclerotic renal artery stenosis, who would be more likely to benefit from renal stenting. Because of limitations of conventional angiography, it is critical that the hemodynamic severity of moderately severe (50% to 70%) atherosclerotic renal artery stenosis lesions be confirmed on hemodynamic measurement. The authors review techniques to optimize patient selection, to minimize procedural complications, and to facilitate durable patency of renal stenting. The authors also review the current American College of Cardiology and American Heart Association guidelines and the Society for Cardiovascular Angiography and Interventions appropriate use criteria as they relate to renal stenting.

Renal Artery Stenosis: When to Revascularize in 2017

Atherosclerotic renal artery stenosis is the leading cause of secondary hypertension; it can also cause progressive renal insufficiency and cardiovascular complications such as refractory heart failure and flash pulmonary edema. Medical therapy including risk factor modification, renin-angiotensin-aldosterone system antagonists, lipid lowering agents, and antiplatelet therapy is the first line of treatment in all patients. Patients with uncontrolled renovascular hypertension despite optimal medical therapy, ischemic nephropathy, and cardiac destabilization syndromes who have severe renal artery stenosis are likely to benefit from renal artery revascularization. Screening for renal artery stenosis can be done with Doppler ultrasonography, computed tomographic angiography and magnetic resonance angiography. Invasive physiologic measurements are useful to confirm the severity of renal hypoperfusion and therefore improve the selection patients likely to respond to renal artery revascularization. Primary patency exceeds 80% at 5 years and surveillance for in-stent restenosis can be done with periodic clinical, laboratory, and imaging follow-up.

Intraprocedural reduction of the veno-arterial norepinephrine gradient correlates with blood pressure response after renal denervation

AIMS

No intraprocedural assessment is currently available to evaluate the extent of nerve ablation by renal denervation (RDN). We prospectively evaluated the association of intraprocedural reduction of renal veno-arterial norepinephrine gradient with blood pressure (BP) response after RDN.

METHODS AND RESULTS

In 46 consecutive RDN patients, the periprocedural norepinephrine veno-arterial difference was defined as veno-arterial norepinephrine gradient. We observed a reduction of the office systolic BP from 176±19 mmHg to 165±24 mmHg (p=0.02) at three months and 163±22 mmHg (p=0.02) at six months. The mean and maximum systolic ABP decreased by 5 mmHg (p=0.03) and 9 mmHg (p=0.02), respectively. There was a decrease of the norepinephrine RV-RA difference from pre- to post-procedural levels (median 186 pg/ml [54;466] vs. 81 pg/ml [0;182], p=0.02). OBP responders (office systolic BP reduction ≥10 mmHg) showed a greater reduction of the norepinephrine gradient compared to non-responders (-290±450 pg/ml vs. -4±106 pg/ml, p=0.01). Patients with a reduction of norepinephrine gradient in both kidneys showed the most pronounced decrease of the systolic OBP (-24±14 mmHg) compared to patients with a reduction of norepinephrine gradient in only one kidney (-7±15 mmHg) or patients without a norepinephrine reduction (-3±19 mmHg, p=0.03 vs. bilateral reduction).

CONCLUSIONS

Measuring renal norepinephrine gradient during RDN may be a method to gauge the extent of renal nerve ablation.

Renal frame count: a measure of renal flow that predicts success of renal artery stenting in hypertensive patients

OBJECTIVES

Renal artery (RA) stenting can improve control of hypertension yet predicting clinical response remains difficult. We sought to determine the role of the renal frame count (RFC) (number of angiographic frames for contrast to reach distal renal parenchyma after initial RA opacification) as a predictor of improvement in blood pressure (BP) after RA stenting.

METHODS

Renal flow was quantified in 68 consecutive patients (age 72.5 ± 9.1 years, 72% male) undergoing RA stenting for refractory hypertension (BP ≥ 140/90 mm Hg despite treatment with two or more antihypertensive medications) by measuring RFC pre-RA stenting. Significant renal artery stenosis (RAS) was defined as a stenosis ≥ 70% by visual estimation on angiography. Baseline and 6-month follow-up BP was recorded. Clinical response was defined by a drop in systolic blood pressure (SBP) >10 mm Hg on the same or fewer number of anti-hypertensive medications.

RESULTS

Patients with RFC > 30 had SBP reduction (43.2 ± 25.7 mm Hg vs. 30.1 ± 31.3 mm Hg, P = 0.067), diastolic blood pressure reduction (9.1 ± 19.0 vs. -0.2 ± 13.4 mm Hg, P = 0.02), and mean arterial pressure reduction (23.8 ± 19.4 vs. 11.8 ± 16.1 mm Hg, P < 0.001) compared to patients with RFC ≤ 30. Furthermore, baseline RFC >30 was associated with a higher rate of clinical response to RA stenting (93.5% vs. 73%, P = 0.027).

CONCLUSIONS

RFC can be used as a clinical predictor of response to RA stenting. RFC > 30 was associated with reduction in BP after RA stenting and was predictive of clinical response. RFC provides a useful intraprocedural tool in assessing the severity of RAS and predicts the likelihood of clinical response following RA stenting.

Plasma Renin Activity Predicts the Improvement in Resistant Hypertension after Percutaneous Transluminal Renal Artery Angioplasty

Objective Percutaneous transluminal renal artery angioplasty (PTRA) has been recommended for the treatment of renovascular resistant hypertension. However, large randomized trials have reported that PTRA did not improve the outcomes compared with optimal medical therapy in patients with renal artery stenosis (RAS). It is important to identify patients with renovascular hypertension who are likely to respond to PTRA. We herein examined whether or not the plasma renin activity (PRA) could predict the improvement in resistant hypertension after PTRA for RAS. Methods and Results A total of 40 patients (mean age: 63±15 years) with unilateral RAS who received PTRA for resistant hypertension were enrolled in this study. Twenty-two (55%) patients experienced a significant reduction in their blood pressure while using few antihypertensive agents at the 3-month follow up. The median PRA was significantly higher in patients using few antihypertensive agents than in those using more [4.2 ng/mL/hr, interquartile range (IQR) 2.6-8.0 vs. 0.8 ng/mL/hr, IQR 0.4-1.7, p<0.001]. To predict the improvement in hypertension after PTRA, a receiver operating characteristic analysis determined the optimal cut-off value of PRA to be 2.4 ng/mL/hr. A multivariate logistic regression analysis showed that higher PRA (>2.4 ng/mL/hr) was an independent predictor of the improvement in hypertension after PTRA (odds ratio: 22.3, 95% confidence interval: 2.17 to 65.6, p<0.01). Conclusion These findings suggest that the evaluation of preoperative PRA may be a useful tool for predicting the improvement in resistant hypertension after PTRA for patients with RAS.

Renal intervention to treat hypertension

Renal artery intervention to treat hypertension is one of the frontiers of ongoing research in combating this epidemic. This article focuses on recent data regarding PTRS and catheter-based renal sympathetic denervation. Despite progress in this field large multicenter, randomized trials that compare these treatment modalities with medical therapy for hypertension are lacking.

Atherosclerotic renal artery stenosis: review of pathophysiology, clinical trial evidence, and management strategies

Renal artery stenosis is prevalent and commonly encountered by cardiovascular specialists. Recently published randomized studies have provoked tremendous controversies in the treatment strategy with regard to renal artery stenting. However, these studies are inconclusive because of major study limitations. As such, cardiovascular specialists are uncertain of the indications or utility of renal revascularization, with differing opinions on management by nephrologists and cardiologists. A greater understanding of this disease process, especially with regard to its functional significance and consequence and treatment strategies based on well-designed clinical trials, is sorely needed. Our review focuses on atherosclerotic renal artery stenosis, with an emphasis on indications for revascularization and review of current trial data.

Atherosclerotic renal artery stenosis: current therapy and future developments

Atherosclerotic renal artery stenosis affects between 2 and 4 million people in the United States alone and likely has a higher prevalence than previously thought. Renal artery stenosis has been increasingly recognized in recent years, especially in patients with cardiovascular disease. It has been associated with hypertension, renal dysfunction, and sudden onset of pulmonary edema. Patients with symptomatic and hemodynamically significant renal artery stenosis are candidates for revascularization. Revascularization is most often accomplished by renal artery stenting, which has high success rates in terms of patency and low complication rates. An important element in managing patients with renal artery stenosis is selecting those patients who are most likely going to benefit from revascularization. This review article focuses on the clinical diagnosis, current treatment options, and future directions regarding treatment of patients with renal artery stenosis.