ABSTRACT
OBJECTIVES: Various indications for internal iliac artery (IIA) revascularisation have been reported. Revascularisations for gluteal ischaemia and buttock claudication remain controversial and uncommon. The objective of the study was to assess the patency of direct conventional revascularisations (CRs) of the IIA in patients with aortoiliac occlusive disease because few studies have focussed on this specific topic. MATERIALS AND METHODS: The charts of all patients who underwent CR of the IIA, between August 2000 and January 2009, were retrospectively reviewed. We recorded for each patient preoperative vascular work-up. All patients were tested for patency on January 2009. A computed tomography (CT) scan was requested if the duplex scan casts any doubt with regard to patency. If non-patent, the last date for confirmed patency was kept for the analysis. Functional outcomes at the proximal level were also collected. RESULTS: We studied 40 patients with occlusive disease. Buttock claudication was observed in 27 patients (66%), including eight (20%) in whom these symptoms were isolated. The 13 other patients had distal claudication or rest pain and documented proximal ischaemia, justifying the IIA revascularisations. We performed 44 conventional direct revascularisations of the IIA concomitant to aorto- or iliofemoral bypasses in these patients. The overall postoperative patency rate was 89%. Five early occlusions of the IIA remained asymptomatic. The median duration of follow-up was 39 months (3-86 months). The survival rate was 95% at 1 year and 86% at 5 years. The primary patency rate of the IIA was 89% at 1 year and 72.5% at 5 years. Buttock claudication disappeared in 23 of the 27 patients (85%), who were symptomatic at the proximal level prior to surgery. CONCLUSION: Direct IIA concomitant revascularisation has an acceptable patency rate in patients undergoing aorto- or iliofemoral bypasses for occlusive disease. When feasible, this technique appears to be safe for the treatment and prevention of buttock claudication.
Subject(s)
Aortic Diseases/surgery , Arterial Occlusive Diseases/surgery , Buttocks/blood supply , Iliac Artery/surgery , Ischemia/surgery , Vascular Patency , Vascular Surgical Procedures , Aged , Aortic Diseases/complications , Aortic Diseases/diagnosis , Aortic Diseases/mortality , Aortic Diseases/physiopathology , Arterial Occlusive Diseases/complications , Arterial Occlusive Diseases/diagnosis , Arterial Occlusive Diseases/mortality , Arterial Occlusive Diseases/physiopathology , Constriction, Pathologic , Female , France , Humans , Iliac Artery/physiopathology , Ischemia/diagnosis , Ischemia/etiology , Ischemia/mortality , Ischemia/physiopathology , Kaplan-Meier Estimate , Male , Middle Aged , Retrospective Studies , Risk Assessment , Risk Factors , Time Factors , Tomography, X-Ray Computed , Treatment Outcome , Ultrasonography, Doppler, Duplex , Vascular Surgical Procedures/adverse effects , Vascular Surgical Procedures/mortalityABSTRACT
INTRODUCTION: The cervical surgery can be complicated of postoperative facial sensory deficits, in particular in using the anterior presternocleidomastoid approach. The purpose of this study was to specify the routes and the links of nerves involved in these sensory deficits (great auricular nerve and transverse cervical nerve with the goal, to deducing, if possible, some modifications of the surgical practices to prevent the deficits. PATIENTS: Ten dissections of the superficial cervical plexus, on preserved anatomical subjects, were made from February till May 2009. Nerves and whole superficial venous network were dissected on all along their route to be able to make several measures of distances and angles. All the data were computerized treated by spreadsheet. RESULTS: The transverse cervical nerve appeared from the posterior edge of the sternocleidomasoid (SCM) muscle in 7.46 ± 1.81 cm s (5,1-10,0) of the clavicle, with an angle of 108.3 ± 8.15° (93-120). Its halving terminal branches was made in 2.92 ± 1.76 cm s (0,4-5,2) of the posterior edge of the SCM muscle, with an angle between these two branches of 74.0 ± 36.8° (40-120). The great auricular nerve appeared from the posterior edge of the muscle SCM in 8.96 ± 1.85 cm (6.4-12.0) of the clavicle, with an angle of 64.5 ± 23.39° (35-110), which modified secondarily to measure 39.5 ± 6.15° (27-45) in the middle of the SCM muscle. At this level, the great auricular nerve and the external jugular vein were almost parallel (1.3° of average difference) and the distance that separated them was 2.24 ± 0.79 cm (0.8-3.5). CONCLUSION: Our study gave us a precise description of the superficial cervical plexus. All the measures allowed the establishment of the routes and the links of these structures to propose peroperating actions to prevent these facial sensory deficits.
Subject(s)
Cervical Plexus/anatomy & histology , Adult , Anthropometry , Cervical Plexus/injuries , Cervical Plexus/surgery , Dissection , Face/innervation , Female , Humans , Intraoperative Complications/prevention & control , Male , Neck Muscles/innervation , Postoperative Complications/prevention & control , Sensation Disorders/etiology , Sensation Disorders/prevention & controlABSTRACT
PURPOSE: To evaluate the agreement and diagnostic accuracy of Contrast enhanced magnetic resonance angiography (CE-MRA), Doppler ultrasound (DUS) and Digital subtraction angiography (DSA) in the assessment of carotid stenosis. METHODS: DUS, CE-MRA and DSA were performed in 56 patients included in the Carotide-angiographie par résonance magnétique-échographie-doppler-angioscanner (CARMEDAS) multicenter study with a carotid stenosis ≥ 50%. Three readers evaluated stenoses on CE-MRA and DSA (NASCET criteria). Velocities criteria were used for stenosis estimation on DUS. RESULTS: CE-MRA had a sensitivity and specificity of 96-98% and 66-83% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 94% and 76-84% respectively for carotid stenoses ≥ 70%. The interobserver agreement of CE-MRA was excellent, except for moderate stenoses (50-69%). DUS had a sensitivity and specificity of 88 and 75% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 83 and 86% respectively for carotid stenoses ≥ 70%. Combined concordant CE-MRA and DUS had a sensitivity and specificity of 100 and 85-90% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 96-100% and 80-87% respectively for carotid stenoses ≥ 70%. The positive predictive value of the association CE-MRA and DUS for carotid stenoses ≥ 70% is calculated between 77 and 82% while the negative predictive value is calculated between 97 and 100%. CE-MRA and DUS have concordant findings in 63-72%, and the overestimations cases were recorded only for carotid stenosis ≤ 69%. CONCLUSION: Combined DUS-CE-MRA is excellent for evaluation of severe stenosis but remains debatable in moderate stenosis (50-69%) due to the risk of overestimations.
Subject(s)
Carotid Stenosis/diagnosis , Imaging, Three-Dimensional , Magnetic Resonance Angiography , Ultrasonography, Doppler , Aged , Aged, 80 and over , Carotid Stenosis/diagnostic imaging , Carotid Stenosis/pathology , Contrast Media , Female , Humans , Image Interpretation, Computer-Assisted , Male , Middle Aged , Predictive Value of Tests , Sensitivity and SpecificityABSTRACT
One hundred brains (first injected in cerebral arteries and veins with latex neoprene or India ink and studied under optic magnification) illustrate this anatomic chapter concerning the microsurgical anatomy of the cisternal segment, the neurovascular relationships, and the blood supply of the IIIrd to the XIIth cranial nerves.
Subject(s)
Cisterna Magna/anatomy & histology , Cranial Nerves/anatomy & histology , Abducens Nerve/anatomy & histology , Glossopharyngeal Nerve/anatomy & histology , Humans , Hypoglossal Nerve/anatomy & histology , Oculomotor Nerve/anatomy & histology , Trigeminal Nerve/anatomy & histology , Trochlear Nerve/anatomy & histology , Vestibular Nerve/anatomy & histologyABSTRACT
SUMMARY: This study of 25 brains at the pontomedullary junction defined the different possible origins of the perforating arteries and lateral spinal arteries in relation to the posterior inferior cerebellar arteries (PICAs). - If the PICA emerges from the common trunk of the AICA-PICA coming from the basilar artery, it never gives perforating arteries or a lateral spinal artery on the lateral surface of the brain stem but supplies blood to a part of the ipsilateral cerebellar hemisphere. - If the PICA arises extradurally at C1, it never gives perforating arteries for the lateral surface of the brain stem, but it gives pial branches for the posterior surface of the medulla oblongata and is always the origin of the lateral spinal artery. - If the PICA emerges in the intradural vertebral artery, it is the source of the perforating arteries for the lateral surface of the brain stem and of the blood supply of the ipsilateral cerebellum.
ABSTRACT
AIM: The aim of this study was to evaluate our results with elective vertebral arteries surgery, to emphasize the indications of such revascularization and to compare it with previous larger studies. METHODS: The medical records of all patients who underwent a pretransversal vertebral artery (VA) revascularization between 1990 and 2004 at our University Hospital were retrospectively reviewed. RESULTS: Forty patients, with a mean age of 60.5 years, met the criteria for VA surgery and accounted for 4.2% of the vascular surgeries involving the brain. Seventeen (42.5%) patients presented with vertebrobasilar insufficiency of hemodynamic origin, 16 (40%) with embolism, and 7 (17.5%) had no neurological symptoms. Direct vertebrocarotid reimplantation was the main procedure performed. No death or stroke occurred preoperatively or during the perioperative period. Mean follow-up was 31 months. Overall survival was 86.9% at 3 years and the primary patency rate was 97.5% at 3 years. CONCLUSION: Our study confirms the good results achieved by the pretransversal conventional VA surgery. This surgery remains few in number despite the fact that about 25% of ischemic strokes occur in the vertebrobasilar region. Vertebrobasilar signs should be better recognized to avoid performing this type of procedure merely based on imaging criteria.
Subject(s)
Arterial Occlusive Diseases/surgery , Vascular Surgical Procedures/methods , Vertebral Artery/surgery , Vertebrobasilar Insufficiency/surgery , Adult , Aged , Angiography, Digital Subtraction , Arterial Occlusive Diseases/complications , Arterial Occlusive Diseases/diagnostic imaging , Female , Follow-Up Studies , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors , Time Factors , Treatment Outcome , Vertebrobasilar Insufficiency/diagnostic imaging , Vertebrobasilar Insufficiency/etiologyABSTRACT
The erosion of the lumbar vertebral bodies by a chronic contained rupture of an infra-renal abdominal aortic aneurysm is a rare event. Chronic contained rupture can cause diagnostic difficulties as there are many clinical presentations, such as: back pain, sciatic pain or an expansive abdominal mass. The diagnosis is sometimes made following an incidental finding on radiological examination. Currently a CT scan is the gold standard diagnostic tool. The outcome following urgent surgical or endovascular repair is equivalent to that of an elective aneurysm repair. We report a case of a 59 year old man admitted for septic rupture of a cutaneous fistula resulting from a false aneurysm in the left groin. Pre-operative CT scan revealed a 6 cm abdominal aortic aneurysm, with chronic contained rupture. This had caused bone erosion of the vertebral body of the third lumbar vertebrae.
Subject(s)
Aneurysm, Ruptured/diagnostic imaging , Aortic Aneurysm, Abdominal/diagnostic imaging , Spinal Diseases/etiology , Adult , Aneurysm, Ruptured/surgery , Aortic Aneurysm, Abdominal/surgery , Chronic Disease , Humans , Male , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
Varicose vein repair often necessitates a distal approach to the great saphenous vein (GSV). The classic method involves a medial pre-malleolar approach. We propose a more distal approach via the medial surface of the foot where there is a cutaneous landmark, which can be used to locate the GSV in a simple, reliable and reproducible fashion. In 20 cadaveric feet, we dissected out the GSV exploiting the above-mentioned cutaneous landmark. We then extended the dissection up as far as the medial pre-malleolar region (from where the GSV is classically approached) in order to be able to compare the diameter of the vein at the two different points (in the foot and in the pre-malleolar region). We also compared the cutaneous landmark with ultrasonographic location of the GSV in 22 feet of healthy subjects. Both dissections and ultrasound examinations demonstrated the reliability of the cutaneous landmark. Moreover, no significant difference was detected in the diameter of the GSV at the two different approach points. This original distal approach to the GSV requires only minor modifications of current practice for varicose veins surgical treatment.
Subject(s)
Saphenous Vein/anatomy & histology , Saphenous Vein/surgery , Aged , Aged, 80 and over , Cadaver , Dissection/methods , Female , Humans , Male , Middle Aged , Reference Values , Reproducibility of Results , Saphenous Vein/diagnostic imaging , Ultrasonography , Varicose Veins/surgeryABSTRACT
The internal iliac arteries (IIA), and especially the distal segment, course very deep in the pelvis and are generally difficult to access surgically. The recent development of simple and reliable methods to investigate proximal ischemia of the lower extremities has led to discovery of more candidates for elective revascularization of the IAA. The classic approaches to the IAA, i.e., the transperitoneal and homolateral retroperitoneal routs have certain disadvantages. We present a new crossed retroperitoneal approach to the IAA and the results of such method in six cadavers. In all six cases, the entire IAA could be exposed without any particular problems. This novel approach to the IAA seems to be both simple and reproducible.
Subject(s)
Iliac Artery/anatomy & histology , Retroperitoneal Space/anatomy & histology , Aged , Aged, 80 and over , Cadaver , Dissection/methods , Female , Humans , Male , Medical IllustrationABSTRACT
We report the case of an aneurysm of the superior gluteal artery that occurred more than ten years after a pelvic trauma. The diagnosis of this uncommon condition is sometimes difficult because of the predominant neurologic symptoms. Rupture can be life-threatening. The patient was treated by an embolization; thereafter a surgical procedure with control of the internal iliac artery and an endoaneurysmorrhaphy was performed. The main characteristics of this pathology are indicated.
Subject(s)
Aneurysm/diagnosis , Buttocks/blood supply , Aneurysm/therapy , Angiography , Embolization, Therapeutic , Female , Humans , Magnetic Resonance Imaging , Middle AgedABSTRACT
We report a case of thoraco-abdominal pseudo-coarctation which developed late after implantation of a cryopreserved arterial allograft. The allograft was placed in a thoraco-abdominal position to treat an aorto-esophageal fistula after colonic esophagoplasty. Follow-up was free of complications for eight Years. The pseudo-coarctation was discovered during the evaluation of hypertension. Surgical treatment involved transdiaphragmatic bypass between the thoracic and infra-renal abdominal aorta. Arterial pressure immediately returned to normal. Twelve Months later, the patient is alive and well with normal blood pressure. A review of the literature revealed rare cases of arterial allograft with a description of the long-term outcome.
Subject(s)
Aorta, Thoracic/surgery , Transplantation, Homologous/physiology , Adult , Aortic Coarctation/etiology , Aortic Coarctation/surgery , Cryopreservation , Esophagoplasty/adverse effects , Humans , Male , Treatment OutcomeABSTRACT
The persistent carotid-vertebrobasilar anastomoses (PCVBA) can be explained by an interruption of the vertebrobasilar system (VBS) embryogenesis. We present two very rare cases of persistent anastomoses: a hypoglossal artery and a type I proatlantal artery, insisting on the angiographic criteria allowing differentiation. After a brief review of the embryogenesis of the VBS, we describe the different types of persistent anastomoses (hypoglossal, type I and II proatlantal, trigeminal and otic arteries). We will insist on the potential risks, not well-known, but typical of each anastomosis. PCVBA usually are incidental findings but imaging follow-up may be required since aneurysms may develop.
Subject(s)
Aneurysm, Ruptured/embryology , Carotid Arteries/abnormalities , Cervical Atlas/blood supply , Hypoglossal Nerve/blood supply , Intracranial Aneurysm/embryology , Intracranial Arteriovenous Malformations/embryology , Vertebral Artery/abnormalities , Aneurysm, Ruptured/diagnostic imaging , Carotid Arteries/diagnostic imaging , Carotid Arteries/embryology , Cerebellum/blood supply , Cerebellum/diagnostic imaging , Cerebellum/embryology , Diagnosis, Differential , Humans , Hypoglossal Nerve/diagnostic imaging , Hypoglossal Nerve/embryology , Intracranial Arteriovenous Malformations/diagnostic imaging , Male , Middle Aged , Radiography , Trigeminal Nerve/blood supply , Trigeminal Nerve/diagnostic imaging , Trigeminal Nerve/embryology , Vertebral Artery/diagnostic imaging , Vertebral Artery/embryologyABSTRACT
To compare the performance of MR-cholangiopancreatography (MRCP) and that of classical anatomy in the depiction of the main pancreatic duct, 50 MRCP examinations were done in patients free of pancreatic disease. Axial and coronal sections 20 mm thick were obtained in a Single Shot Fast Spin Echo (SSFSE) sequence. The following were analyzed: (1) visibility of pancreatic duct structures, (2) form of the main pancreatic duct, (3) various angulations of the duct and (4) diameter of the duct. Anatomic variants were noted. These findings were compared with anatomic and radio-anatomic (ERCP) data in the literature. The main pancreatic duct was visualized in 100% of cases and the accessory pancreatic duct in 61%. The form, diameter and angulations of the various segments of the pancreatic duct were similar to those reported in the literature. These findings are reported in the axial and coronal planes. Comparison with major anatomic classifications was not possible. MRCP enables in vivo anatomic exploration of the main pancreatic duct. Horizontal sections provided new radio-anatomic information. The technique nevertheless remains limited by poor spatial resolution.
Subject(s)
Cholangiopancreatography, Endoscopic Retrograde/methods , Echo-Planar Imaging/methods , Pancreatic Ducts/anatomy & histology , Pancreatic Ducts/diagnostic imaging , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle AgedABSTRACT
OBJECTIVE: Removal of accessory fibres coming from the sub-stellar thoracic chain to the heart during infra-stellate surgical upper thoracic sympathectomy (ISS) may be responsible for a decreased heart rate to workload relationship during exercise following surgery. We hypothesised that heart rate would decrease not only following right ISS. METHODS: We performed repeated bicycle incremental exercise tests in 11 control subjects (26.9+/-9.5 years, 61.4+/-12.4 kg, 167+/-10 cm), and 11 patients (29.8+/-10 years, 59.3+/-12.0 kg, 168+/-7 cm) referred for bilateral ISS: results are mean+/-standard deviation. Surgery was performed at two distinct times allowing to study the consequences of unilateral and bilateral sympathectomy to confirm whether a significant relative bradycardia was constant and dependent on the operated side. RESULTS: For control subjects, test durations were 13.55+/-3.29, 14.09+/-4.01 and 13.00+/-3.26 min and heart rates were 187+/-7, 187+/-8 and 186+/-7 beats min(-1) at the first, second and third test, respectively. Although time to exhaustion was comparable to controls and unchanged between tests: 12.32+/-2.87, 12.3+/-2.90, 12.33+/-3.76 min, heart rate at maximum exercise decreased significantly from 176+/-16 to 164+/-15, and 148+/-15 beats min(-1), before, following unilateral and bilateral ISS, respectively. The operated side did not allow for the prediction of the effect of unilateral sympathectomy. CONCLUSIONS: Patients should be informed of the exercise bradycardia resulting from ISS, although clinical tolerance seems excellent in endurance exercise. Contrary to previous reports at rest, during exercise no right-sided dominance was observed. These findings are consistent with reports of random distribution of sub-stellate cardiac fibres from anatomical studies.
Subject(s)
Bradycardia/etiology , Sympathectomy/adverse effects , Adult , Exercise Test , Exercise Tolerance , Female , Functional Laterality , Heart Rate/physiology , Humans , Male , Middle Aged , Stellate Ganglion , Sympathectomy/methodsABSTRACT
A case of a "double hepatomesenteric artery", i.e. two persisting hepatic arteries arising from the superior mesenteric artery, is reported. Also observed was a lack of systematisation of the pancreaticoduodenal arteries. The variant, which does not appear to have been previously reported in the literature, was observed when dissecting the vessels of the duodenal bulb in a preserved male cadaver injected with neoprene latex. Its embryological origin, as well as the clinical, radiological (diagnostic or interventional) and surgical implications, are discussed.
Subject(s)
Hepatic Artery/abnormalities , Liver/blood supply , Mesenteric Artery, Superior/abnormalities , Pancreas/blood supply , Cadaver , Dissection , Humans , Risk Assessment , Sensitivity and SpecificityABSTRACT
OBJECTIVES: The purpose of this study was to: 1) detail the clinical presentations of diseases requiring revascularization of the vertebral artery and recall the guidelines of the 1975 Ad Hoc committee; 2) identify the explorations needed to detect vertebro-basilary insufficiency; 3) define operative indications since no consensus has been reached. PATIENTS AND METHODS: We reviewed retrospectively the files of 34 patients who underwent revascularization of the vertebral artery between January 1990 and December 2000. RESULTS: Surgery of the vertebral artery accounted for 4.6% of our vascular surgery cases involving the brain. Fifty percent of the cases of vertebro-basilary insufficiency were caused by hemodynamic disorders and 26.5% by embolism; 23.5% of the patients had no neurological sign. The most frequent neurological signs were vertigo (44%), balance disorders (41%), long pathway involvement (32%). Vertebro-basilary reimplantation was performed in 76% of the cases. There were no cases of stroke and no deaths during the early postoperative period. There was one case of asymptomatic thrombosis. Mean follow-up was 33.6 months with no patients lost to follow-up. Overall survival was 85.29% at 3 years with patent arteries in 97.06% of the cases at 3 years. CONCLUSION: Our series is in agreement with others reported in the literature, emphasizing the good outcome achieved after vertebral artery surgery. Surgery helps improve signs of vertebro-basilary insufficiency with little operative risk. This surgery is rarely indicated but must be recognized. One must also resist the temptation to "treat images".
Subject(s)
Vertebrobasilar Insufficiency/surgery , Female , Follow-Up Studies , Humans , Male , Middle Aged , Retrospective StudiesABSTRACT
BACKGROUND: Vertebrobasilar (VB) strokes appear to have the same causes as carotid strokes. Obstructive lesions of proximal vertebral arteries probably occur in about 30% of stroke patients. PURPOSE: Our aim was to assess the validity of color Doppler sonography compared to selective intra-arterial angiography in the quantification of proximal vertebral artery stenoses. MATERIALS AND METHODS: A prospective blind study of 316 vertebral arteries was undertaken between 1996 and 1998. One hundred and fifty-eight patients with cerebrovascular disorders without cerebral hemorrhage were studied consecutively by frequency or amplitude color Doppler flow imaging and intra-arterial angiography. The lesions were quantified by morphological and hemodynamic criteria and classified into 6 groups: 0% 207 arteries; 1-29% 32 arteries; 30-49% 29 arteries; 50-69% 13 arteries; 70-99% 23 arteries; 100% 12 arteries. RESULTS: Ten of the 12 occlusions were identified, the 2 false-negatives were due to 2 revascularized vessels. Moderate stenoses (<50%) were differentiated from tight stenoses (>50%) using hemodynamic criteria. The majority of false-negative stenoses (38) in the different groups were related to intrathoracic or very deep origin of the artery, anechogenic stenosis or a tortuous vessel. Stenoses greater than 70% were diagnosed in 71% of cases with a specificity of 99%. The kappa value was 0.80. CONCLUSION: Duplex sonography should be proposed first in VB attacks or stroke to detect and quantify vertebral artery stenoses for surgery and angioplasty.
Subject(s)
Arterial Occlusive Diseases/diagnostic imaging , Vertebral Artery/diagnostic imaging , Arteriosclerosis/complications , Arteriosclerosis/diagnostic imaging , Cerebral Angiography , Double-Blind Method , False Positive Reactions , Humans , Prospective Studies , Stroke/diagnostic imaging , Ultrasonography, Doppler, ColorSubject(s)
Ischemia/surgery , Knee/blood supply , Leg/blood supply , Aged , Aged, 80 and over , Angiography , Humans , Ischemia/diagnostic imaging , Male , Middle Aged , Treatment Outcome , Vascular PatencyABSTRACT
Percutaneous transluminal angioplasty (PTA) can be performed safely in arteries below the knee by using current coaxial catheters. This study includes 37 consecutive patients treated between March 1992 and March 1999 by PTA for limb-threatening infrageniculate occlusive artery disease. The mean duration of follow-up was 28 months. Limb salvage was achieved in 32 patients. The actuarial limb salvage rate at 2 years was 87 +/- 6%. This study shows that PTA was a viable alternative to surgical treatment for management of critical lower extremity ischemia in carefully selected patients. Limb salvage rates after PTA and conventional surgical revascularization seem comparable. Based on these findings, we recommend that PTA be attempted, whenever possible, for initial treatment of patients presenting critical, limb-threatening ischemia due to isolated or multiple stenoses of below-knee arteries.