Iatrogenic acute limb ischemia with complete traumatic rupture of the popliteal artery associated with total knee arthroplasty.

Acute limb ischemia (ALI) related to total knee arthroplasty (TKA) is rare. Most occlusions are caused by thrombus formation in the popliteal artery (PA). Currently such cases are revascularized using less invasive approaches such as endovascular therapy or Fogarty thrombectomy. We report a case of ALI in a 65-year-old woman with complete rupture of the PA due to a TKA procedure. She had resting pain and motor paralysis in her right lower extremity after TKA. Contrast-enhanced computed tomography showed occlusion of the right femoropopliteal artery. Subsequently, she was referred to our hospital with a diagnosis of ALI. Initially, a less invasive revascularization procedure was unsuccessfully attempted. Therefore, we performed an emergency distal bypass and succeeded in revascularization. Intraoperative examination revealed a complete rupture of the PA. Postoperatively, the patient exhibited no signs of myonephropathic metabolic syndrome. Although there was significant motor impairment, the affected limbs were successfully salvaged. ALI with complete rupture of the PA associated with TKA has not been reported previously. In cases of iatrogenic ALI after TKA, it would be essential to consider diagnostic and revascularization methods that account for the possibility of severe injury to the PA. Learning objective: Acute limb ischemia after total knee arthroplasty is a rare and life- and limb-threatening condition. The underlying pathological mechanism is often thrombus occlusion due to mechanical stimuli of the popliteal artery (PA). There are no established treatments for this condition, and less invasive approaches such as endovascular procedures and Fogarty thrombectomy are often used. However, in cases involving severe damage to the PA, bypass surgery may be necessary, and revascularization procedures should be considered accordingly.

Poor short-term outcomes for prognostic high-risk patients with chronic limb-threatening ischemia undergoing endovascular therapy.

BACKGROUND: The prognosis of chronic limb-threatening ischemia (CLTI) is poor, with an expected life expectancy of 2 or more years, which significantly influences treatment decisions. However, death may occur at the early stages of treatment for wound healing, and aggressive treatment may limit the quality of life of such patients. In patients with CLTI undergoing endovascular therapy (EVT), the Wound, Ischemia, and foot Infection (WIfI) clinical stage, male sex, older age, non-ambulatory status, low body mass index, and dialysis have been reported as predictors of mortality risk. However, most studies have not fully investigated the WIFI clinical stage as a prognostic predictor of CLTI. This study aimed to evaluate short-term prognosis and wound healing rates using the prognostic predictors (PPs) indicated above in risk-stratified patients with CLTI who underwent EVT. METHODS: This retrospective single-center observational study included 61 CLTI patients undergoing EVT from April 2020 to October 2022. The patients were divided into a high-risk group (PPs ≥ 4, n = 20) and low-risk group (PPs ≤ 3, n = 41) according to the number of PPs. Survival and wound healing rates within one year were compared between these two groups. RESULTS: The mean age of the patients was 74.7 ± 1.6 years, and 42 (68.9%) were male. Among these patients, the high-risk group compared with the low-risk group had a significantly worse survival rate within one year (46.4% vs. 84.7%, log-rank p < 0.001). Fifteen patients died within one year. Of these, seven deaths were cardiovascular deaths and six were deaths from infectious diseases. Cox proportional hazards analysis showed that WIfI clinical stage 4 (p = 0.043, hazard ratio [HR] = 4.85) and the male sex (p = 0.037, HR = 6.34) influenced the prognosis of this population. The high-risk group tended to have a worse wound healing rate within one year than that had by the low-risk group (55.4% vs. 83.0%, log-rank p = 0.086). CONCLUSIONS: The assessment of short-term prognosis and wound healing rates using PPs may be useful. Discussing the results of short-term clinical outcome assessments with patients should be considered when determining their individualized treatment plans.

Characteristics of recurrent in-stent restenosis after second- and third-generation drug-eluting stent implantation.

BACKGROUND: In second- and third-generation drug-eluting stent (DES) era, in-stent restenosis (ISR) is not commonly seen. However, a few patients still need repeat revascularizations for recurrent ISR even after second- and third-generation DES implantation. METHODS: From January 2012 to March 2017, 2339 lesions underwent second- and third-generation DES (Nobori, Promus Element, Resolute Integrity, Xience, Ultimaster and Synergy) implantation, of which 95 lesions (4.1%) underwent revascularization for first ISR. All lesions were divided into two groups of recurrent ISR group and non-recurrent ISR group. After successful optical coherence tomography (OCT) guided revascularization for all lesions, we investigated characteristics of recurrent ISR, and 2 years follow-up were completed. RESULTS: The mean age was 70.8 ± 11.7 years, and 73.2% were males. Among 56 DES-ISR lesions which were assessed by OCT, recurrent ISR was seen in 33.9% (N = 19) at 2 years follow-up after revascularization for first ISR. Serum low-density lipoprotein-cholesterol (LDL-C) level was higher in recurrent ISR group compared with non-recurrent ISR group (114.1 ± 53.9 mg/dl vs. 90.9 ± 27.8 mg/dl, P = 0.04) and heterogeneous tissue pattern was more frequently found in recurrent ISR group compared with non-recurrent ISR group (63.2% vs. 27.0%, P = 0.03). Multivariate analysis identified a heterogeneous tissue pattern (odds ratio 3.71; 95% confidence interval 1.09-12.59; P = 0.03) as an independent predictor of recurrent restenosis. CONCLUSION: Recurrent ISR of second- and third-generation DES was associated with heterogeneous tissue pattern of first ISR, and high LDL-C level was associated with recurrence.

In-stent restenosis assessed with frequency domain optical coherence tomography shows smooth coronary arterial healing process in second-generation drug-eluting stents.

INTRODUCTION: The pathophysiology and mechanism of in-stent restenosis (ISR) after implantation of second-generation drug-eluting stents (DESs) are not fully clear. We compared the morphological characteristics of ISR between first- and second-generation DESs using frequency domain optical coherence tomography (OCT). METHODS: Patients who underwent follow-up coronary angiography (CAG) after first-generation (CYPHER™ and TAXUS™) and second-generation (Nobori®, PROMUS Element™, Resolute Integrity and XIENCE) DES implantations were examined. ISR was defined as lesions of over 50% diameter stenosis at follow-up CAG. Frequency domain OCT was performed at the time of revascularisation of ISR. Tissue morphology was assessed at minimum lumen area. OCT images of DESs at both early (≤ 1 year) and late (> 1 year) phase follow-up were compared. RESULTS: On qualitative OCT assessment, the ratios of homogeneous, layered, heterogeneous without-attenuation and heterogeneous with-attenuation morphologies were 57.1%, 17.1%, 20.0% and 5.7%, respectively, for second-generation DES ISR (n = 35), and 16.7%, 25.0%, 25.0% and 33.3%, respectively, for first-generation DES ISR (n = 36). At late phase follow-up, homogeneous morphology was significantly more common for second-generation DES ISR compared to first-generation DES ISR (first-generation: 8.0% vs. second-generation: 50.0%; p < 0.01) while heterogeneous with-attenuation morphology was significantly more common for first-generation DES ISR (first-generation: 44.0% vs. second-generation: 5.6%; p < 0.01). CONCLUSION: Homogeneous tissue morphology was more frequently found for second-generation than first-generation DES ISR, especially in the late phase. This suggested that neointimal hyperplasia was the main mechanism in second-generation DES ISR, and that the neointima was stabilised, much like in bare metal stent implantation.

Simple balloon dilation for drug-eluting in-stent restenosis: an optical coherent tomography analysis.

BACKGROUND: Although drug-eluting stent (DES) has significantly reduced restenosis, the treatment of DES-in-stent restenosis (ISR) remains a challenge with high restenosis rate. METHODS: We examined whether morphologic appearance of restenosis tissue by optical coherent tomography (OCT) had an impact on outcomes after balloon angioplasty for DES-ISR. The morphologic appearance of restenosis tissue was qualitatively assessed for tissue structures such as homogeneous, layered, and heterogeneous patterns. RESULTS: Using OCT, 50 patients with DES-ISR were divided into 2 groups: 25 lesions with homogeneous or layered patterns (homo/layered group) and 25 lesions with heterogeneous patterns (hetero group). Acute gain was larger in the hetero group (1.33 ± 0.41 mm vs. 1.06 ± 0.32 mm in the homo/layered group, P = 0.03). On intravascular ultrasound analysis, post-procedural percent neointimal area was smaller in the hetero group (27.4 ± 9.2% vs. 34.0 ± 11.2% in the homo/layered group, P = 0.05). Angiographic follow-up was performed in 37 lesions (74%). Follow-up minimal lumen diameter was larger in the hetero group (1.75 ± 0.89 mm vs. 1.01 ± 0.81 mm in the homo/layered group, P = 0.04). Target lesion revascularization rates tended to be lower in the hetero group (20% vs. 43% in the homo/layered group, P = 0.12). CONCLUSIONS: Balloon angioplasty was more effective for DES-ISR with heterogeneous tissue appearance than DES-ISR with homogeneous/layered tissue appearance. OCT assessment of DES-ISR morphology may be a useful adjunct in determining clinical strategies. Simple balloon dilatation is a possible treatment strategy for DES-ISR lesions with a heterogeneous appearance on OCT images.

Association of morphologic characteristics on optical coherence tomography and angiographic progression patterns of late restenosis after drug-eluting stent implantation.

OBJECTIVES: To gain insight into the pathophysiology of late drug-eluting stent (DES) restenosis. BACKGROUND: Restenosis of DES has a different time course from that of bare metal stents. METHODS: Patients who underwent follow-up coronary angiography (CAG) twice (six to nine months and 18 to 24 months) after DES implantation were examined using optical coherence tomography (OCT). All lesions with target lesion revascularization at first follow-up were excluded. Late catch-up was defined as lesions that progressed from less than 50% diameter stenosis (DS) at the first CAG to more than 50% DS at the second CAG. Lesions with the late catch-up were further divided into two groups; lesions with jump-up (less than 25% DS at the first CAG) and lesions with gradual progression (25-50% DS at the first CAG). RESULTS: Of the 25 patients who had late ISR, 23 patients (10 jump-up/13 gradual progression) were examined with OCT at late follow-up and enrolled in this study. In the qualitative OCT assessment, each ratio of homogeneous, layered, heterogeneous with or without attenuation tissue morphologies were in jump-up group, and gradual progression group were 0% and 15%, 0% and 23%, and 60% and 8%, and 40% and 54%, respectively. All of jump-up group showed heterogeneous restenotic tissue, while 62% of gradual progression group showed heterogeneous restenotic tissue (P = .04). CONCLUSIONS: These findings suggest different pathophysiology of the late catch-up after DES implantation between the jump-up and gradual progression groups.