Editor's choice--hybrid treatment of thoracic, thoracoabdominal, and abdominal aortic aneurysms: a multicenter retrospective study.

OBJECTIVES: The aim of this study was to assess the results of hybrid techniques for the treatment of thoracic, thoracoabdominal, and abdominal aortic aneurysms based on multicenter results and the various series regarding hybrid procedures reported in the literature. METHODS: The results of 76 hybrid procedures performed in 19 French university hospital centers between November 2001 and October 2011 were collected. There were 50 men and 26 women, mean age 68.2 (35-86) years. All patients were considered at high risk (ASA≥3) for conventional surgery. Aneurysms involved the thoracic, abdominal, and thoracoabdominal aorta in five, 14, and 57 cases respectively. There were 11 emergent repairs. The revascularization of four visceral arteries was performed in 38 cases. Between one and three visceral arteries were revascularized in the other cases. Visceral artery debranching and stent graft deployment were performed in a one-stage procedure in 53 cases and in a two-stage procedure in 23 cases. RESULTS: There were 26 (34.2%) postoperative deaths. Nine of the survivors developed paraplegia, of which one resolved completely. Bowel ischemia occurred in 13 cases (17.1%), and one patient was treated by a superior mesenteric artery bypass. Four patients required long-term hemodialysis. Postoperative computed tomography scan showed a type II endoleak in two patients. CONCLUSIONS: Morbidity and mortality in this study were greater than previously reported. Candidates for hybrid aortic repair should be carefully selected.

[Exercise-induced renal ischemia after kidney transplantation: report of two cases]. / Ischémie rénale d'effort sur rein transplanté : à propos de deux cas.

INTRODUCTION: Renal transplant patients are high cardiovascular risk patients. Regular ultrasound surveillance of the renal transplant artery and the iliac artery upstream from the anastomosis is required to detect potential arterial stenosis. The purpose of this article was to illustrate the hemodynamic impact of exercise in such patients and the screening efficiency of Doppler ultrasound stress testing. METHODS: Two renal transplant patients were hospitalized in our center for impaired renal function, worsening hypertension, and intermittent claudication. This association of peripheral vascular disease and renal dysfunction led us to perform a Doppler ultrasound stress test to search for vascular stenosis upstream from the graft. Hemodynamic fluctuations in the ipsilateral leg were recorded during flexion-extension exercises. RESULTS: Iliac artery lesions were found in both patients: the Doppler examination showed decreased systolic velocity in the graft artery during exercise, compatible with iliac steal syndrome. Surgical treatment was performed in both patients. After surgery, the control Doppler ultrasound stress test showed that systolic flow did not decline in the graft vessels during exercise. Renal function stabilized in one patient and improved in the other; claudication disappeared after surgery. CONCLUSION: Doppler ultrasound stress testing can be a valuable tool for detecting exercise-induced renal graft ischemia in transplant patients. Its screening performance should be determined in a larger population before routine use.

Patency of direct revascularisation of the hypogastric arteries in patients with aortoiliac occlusive disease.

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.

[Surgical-site infections following varicose vein surgery according to a continuous series of 408 interventions in a teaching hospital]. / Infections du site opératoire sur ablation de varices d'après une série continue de 408 interventions réalisées dans un centre hospitalier universitaire.

OBJECTIVE: To determine the incidence of surgical-site infections (SSI) following varicose vein surgery in the vascular surgery ward of a French teaching hospital. PATIENTS AND METHODS: A prospective surveillance of SSI was conducted during one year, with a 30-day postoperative follow-up. SSI cases were identified by using the definitions of the Centers for Disease Control (CDC, USA). Data acquisition and analysis were performed with the Epi-Info 6.04 software (CDC). RESULTS: Three quarters of the 408 included interventions were characterized by a NNIS score equal to 0. All patients underwent a hair removing practice before intervention. Hair removing methods were very heterogeneous and often not in accordance with national recommendations (e.g. mechanic shaving for 44.6% of patients). The incidence of SSI was 1.2% (95% confidence interval=[0.2-2.2]). All infections were identified after hospital discharge. Four infected patients out of five presented obesity or excess weight, and two patients had diabetes mellitus. The mean age of infected patients was significantly higher than non-infected ones (70.4 years versus 52.0; p<0.01). All SSI had consequences like rehospitalization, reintervention, or antimicrobial therapy. CONCLUSION: According to our results, SSI following varicose vein surgery are scarce and mainly concerned high-risk patients. However, in an aim of prevention, it seems necessary to homogenize hair removing methods in this ward.

Functional outcome of hypogastric revascularisation for prevention of buttock claudication in patients with peripheral artery occlusive disease.

We have defined proximal lower limb ischaemia as a decrease in Exercise-transcutaneous oxygen pressure (TcPO(2)) lower than minus 15mmHg at the buttock level in patients with peripheral artery occlusive disease. The purpose of this study was to objectively evaluate the benefits of direct versus indirect revascularisation of internal iliac arteries (IIAs) for prevention of buttock claudication in this population. We retrospectively reviewed the charts of proximal ischaemia patients who underwent revascularisation and both preoperative and postoperative stress TcPO(2) testing. Revascularisation procedures were classified as either direct revascularisation, including percutaneous transluminal angioplasty and internal iliac artery bypass, resulting in a direct inflow in a patent IIA (group 1) or indirect revascularisation, including aortobifemoral bypass and recanalisation of the femoral junction on the ischaemic side, resulting in indirect inflow from collateral arteries in the hypogastric territory (group 2). Patency was checked 3 months after revascularisation in all cases. Treadmill exercise stress tests were performed before and after revascularisation using the same protocol designed to assess pain, determine maximum walking distance (MWD) and measure TcPO(2) during exercise. In addition, ankle-brachial indices (ABIs) were calculated. Between May 2001 and March 2008, a total of 93 patients with objectively documented proximal ischaemia underwent 145 proximal revascularisation procedures using conventional open techniques in 109 cases and endovascular techniques in 36. Direct revascularisation was performed on 50 limbs (35%) (group 1) and indirect revascularisation on 95 limbs (65%) (group 2). The mean interval between revascularisation and stress testing was 60+/-74 days preoperatively and 149+/-142 days postoperatively. No postoperative thrombosis was observed. Buttock claudication following revascularisation was more common in group 2 (p<0.001). No difference was observed between the two groups with regard to improvement in MWD (365 / 294 m) and ABI (0.20/0.22). Disappearance of proximal ischaemia was more common after direct revascularisation (p<0.01). The extent of lesions graded according to the TASC II classification appeared not to be predictive of improvement in assessment criteria following revascularisation. Conversely, patency of the superficial femoral artery was correlated with improvement (p<0.01). This study indicates that direct revascularisation, if feasible, provides the best functional outcome for prevention of buttock claudication.

First report of an ilio-popliteal bypass through the greater sciatic foramen. Case report.

A 47 year-old man, who had a history of pelvic radiotherapy for the treatment of testicular tumour 30 years ago, was referred with minor tissue loss of the right lower extremity, grade III, category 5 of the Rutherford classification. His groin region presented with severe radiation damage. Arteriography demonstrated the occlusion of external iliac and femoral arteries. Revascula-risation was performed in the lateral decubitus position, with a ringed polytetrafluoroethylene (PTFE) graft bypass between normal common iliac and popliteal arteries through the greater sciatic foramen. Quick healing was observed. Patient is well 6 months postoperatively. Immediate and 6 month postoperative imaging demonstrated the good patency of the graft. A duplex ultrasound performed 6 month postoperatively showed no significant compression while the patient was in the sitting position.

[Infrarenal aortic pseudo-aneurism due to Coxiella burnetii]. / Pseudo-anévrisme aortique sous-rénal à Coxiella burnetii.

Peripheral vascular expressions of Coxiella burnetti Q fever are not well known. Endocarditis with negative blood culture is the most frequent clinical presentation of chronic Q fever. To date, very few cases of aneurisms or vascular grafts infections have been described. We report the case of a 54-year-old man who presented an infrarenal abdominal aorta infection, leading to a giant pseudo aneurismal formation. Blood serology and polymerase chain reaction amplification identified C. burnetti from the aortic thrombus after pseudo aneurism surgery. The treatment associated infrarenal abdominal aorta repair using a cryopreserved aorta allograft, and long-term antibiotic therapy.

Surgery of the pretransversal vertebral artery: indications and results.

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.

[Spinal destruction caused by chronic contained rupture of an infra-renal abdominal aortic aneurysm]. / Erosion vertébrale par rupture chronique d'un anévrysme de l'aorte abdominale sous-rénale.

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.

Endovascular stent-graft placement in the descending aorta through an ascending aorto-bifemoral bypass.

PURPOSE: To report a combined conventional and endovascular strategy to treat a descending aorta anastomotic aneurysm. CASE REPORT: A 60-year-old man with previous obliteration of the infra renal aorta suffered from bilateral lower limb acute ischemia. Lower limb vascularization was provided by a previous thoraco-bifemoral bypass. Computed tomography and angiography revealed an aortic anastomotic false aneurysm and an embolic aspect of the first centimeters of the graft. Treatment combined revascularisation of the lower limbs by an ascending aorta bifemoral bypass through a median sternotomy and endovascular coverage of the false aneurysm by stent-graft placement in the descending aorta. Stent-grafts were introduced through a graft's limb and across the anastomosis in the ascending aorta. Imaging at 3 months revealed no endoleak and perfect patency of the bypass. CONCLUSION: This case illustrates how combined endovascular and conventional procedures can minimize surgical risks in complex cases.

Anatomical basis of an original pedal approach to the great saphenous vein for surgery.

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.

[Results of surgical treatment for renal artery dysplasia]. / Résultats de la prise en charge chirurgicale des dysplasies des artères rénales.

PURPOSES: To retrospectively assess functional results of surgical treatment for renal artery dysplasia. PATIENTS AND METHOD: From January 1992 to December 2001, 11 symptomatic patients including 9 women (mean age 47 years, range 23-67), underwent surgery for renal artery dysplasia. Three patients presented with normalized hypertension, three others presented with isolated systolic hypertension, and the five remaining presented with grade II or III hypertension. Angiograms showed evidence of dysplasia of 16 renal arteries. Six arteries showed stenosis (37.5%), four aneurysms (25%), four both (25%), and two arteries showed wall irregularities (12.5%). Endovascular revascularizations were performed in five patients (45%) during the treatment of six renal arteries (37.5%). All endovascular procedures were angioplasties without any stent placement. Six patients (55%) underwent conventional procedures (in situ or ex-situ surgery) for the treatment of seven renal arteries (44%). RESULTS: In the short term, the treatment had a significant decrease on the systolic arterial pressure (p=0.019) and in the number of drugs used (p=0.009), but was not significant in the diastolic arterial pressure (p=0.084). The benefits persisted after two years of follow-up (PAS, p=0.023, PAD, p=0.047, drugs p=0.03). Benefits persisted in all of the six patients who had had hypertension for less than five years. There was 60% functional failure in the treatment of the five patients with a more than five years history of hypertension. CONCLUSION: This study confirms the short and long term's beneficial results of the surgical treatment of symptomatic renal artery dysplasia. Rapid care of those patients should optimize the functional results.

Systematic diagnostic approach to proximal-without-distal claudication in a vascular population.

BACKGROUND: Very few observations of proximal-without-distal claudication have been reported in the literature. This is likely due to the use of questionnaires limiting vascular claudication to the calves and to the problems encountered in attributing unexplained "buttock" claudication to a vascular origin. METHODS: During a 2 1/2-year period, we searched for proximal-without-distal exercise-related pain with the San Diego claudication questionnaire among some 2000 patients referred for lower limb arterial investigations. Of these patients, 97 presented no contraindication to treadmill testing and were investigated with exercise transcutaneous oxygen pressure (tcpO2). We used buttock tcpO2 (DROP index<-15 mm hg) to argue for the presence of ischemia on the corresponding side. RESULTS: Ischemia consistent with symptoms was found in 61 patients, whereas pain on one or both sides without underlying ischemia was found in 36 patients, suggesting a non-arterial origin of the symptoms. More than half of the patients with proximal-without-distal claudication and underlying exercise-related ischemia had been suffering for more than 2 years before they were referred to the laboratory. Eleven of the patients were treated. The treatment was successful in all but one of them. CONCLUSIONS: An important delay before diagnosis is frequently observed in proximal-without-distal claudication. TcpO2 is useful in attributing proximal exercise-related pain to a vascular origin. Given the number of detected and successfully treated patients in this small monocentric study, it is surprising that so few observations have been published to date, suggesting that proximal-without-distal arterial claudication is most likely an underestimated diagnosis.

[Endovascular treatment for obstructive disease of the aortoiliac bifurcation by the kissing stent technique]. / Traitement endovasculaire par "kissing stent" des lésions oblitérantes du carrefour aorto-iliaque.

PURPOSE: To evaluate short and medium-term results of endovascular repair of the aortoiliac bifurcation for occlusive disease by the kissing stent technique. METHOD: Twenty patients were included in this retrospective study between May 1999 and November 2002 (13 men, mean age 58 years, range 42-86). Fifteen were treated for bilateral common iliac artery stenosis (75%), four for unilateral common iliac artery occlusion with or without controlateral stenosis (20%), and one for bilateral common iliac artery occlusion (5%). Each patient had a clinical examination and dupplex-scan prior to discharge, at three months, twelve months then yearly. RESULTS: All procedures were successful. Forty balloon expandable stents were deployed in the kissing position (mean length and diameter, 45 mm and 9 mm). Nine other stents were also deployed either in the abdominal aorta (one patient) either in the lower portion of the common iliac artery. Intra-operative complications were represented by one hematoma of the groin region treated surgically, one emboli of the femoral bifurcation treated by Forgarty balloon embolectomy, three dissections of the common iliac arteries treated by stenting, and one internal iliac artery occlusion not treated. Mean follow-up was 21 months (range 3-36). Three significant restenoses (>50%) were diagnosed during this period and one patient had an additional transluminal procedure. No intra-stent occlusion was found. Primary and secondary cumulative patencies at 12 and 36 months were respectively 94.7%, 84,4% and 100%, 89%. CONCLUSION: We confirm the feasibility, and the reliability of endovascular aorto-iliac kissing stent reconstruction in occlusive disease for selected patients.

Transcutaneous oxygen pressure measurements (tcpO2) at ankle during exercise in arterial claudication.

AIM: Although a time consuming technique, tcpO2 provides complementary information as compared to other tests. Simultaneous recording of systemic and peripheral oxygen pressure changes with exercise could be interesting to confirm that local hypoxemia is of arterial origin, but accuracy versus gold standard arteriography and objectively determined cut-off points to be used in arterial claudication at the ankle are not reported. EXPERIMENTAL DESIGN: retrospective plus prospective study. SETTING: institutional practice, ambulatory care. PATIENTS: 100 patients suffering stage 2 claudication (group A) were retrospectively studied to objectively define cut-off points derived from tcpO2 recordings to be used in exercise testing. Then, applicability and reproducibility of these cut-off points were analysed prospectively in another 50 patients (group B). INTERVENTION: tcpO2 was measured on both calves and with a chest reference electrode. Arteriography on each side was quoted positive for a diameter stenosis superior to 75% or occlusion on the aorto-popliteal axis or of all-3-calf arteries. RESULTS: The best performance was obtained with tcpO2 changes from rest at the calf normalised to eventual chest changes (DROP) during or following the treadmill test. Optimal cut-off point determined through ROC curve analysis for DROP was -15 mmHg in group A. Applying this cut-off point in group B provided a 86/84% sensitivity/specificity and showed excellent reproducibility. CONCLUSIONS: TcpO2 measurement on the calf during exercise could be useful in a selected population of patients with claudication of questionable vascular origin and/or when other non-invasive investigations cannot be performed.

[Aneurysm of the superior gluteal artery]. / Anévrysme de l'artère glutéale supérieure.

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.

Reproducibility of proximal and distal transcutaneous oxygen pressure measurements during exercise in stage 2 arterial claudication.

AIM: Although transcutaneous oxygen pressure measurements (tcpO2) are largely used in the investigation of vascular patients, its reproducibility is still debated. Indeed an unpredictable gradient exists between arterial and transcutaneous oxygen pressure. We hypothesised that indices taking into account changes over time and independent of absolute starting values would be more reproducible than other indices. EXPERIMENTAL DESIGN: comparative test-retest procedure (1 to 13 days between tests). SETTINGS: institutional practice, ambulatory care. PATIENTS AND PARTICIPANTS: 15 subjects with stage 2 claudication. INTERVENTIONS: tcpO2 recordings at rest and at exercise during the 2 treadmill tests. MEASURES: calculation of the Delta-from-rest of oxygen pressure index (limb tcpO2 changes minus chest tcpO2 changes), of the resting - or minimal values attained during exercise - of absolute tcpO2 and of the regional perfusion index (regional perfusion index: ration of limb to chest). RESULTS: Both absolute tcpO2 and regional perfusion index at rest showed low reproducibility. During exercise the best reproducibility was attained through Delta-from-rest of oxygen pressure index calculation. Equations from the linear regression analysis (test 2 versus test 1) were 0.88 x -4.2 (r(2)=0.82) at the buttock level and 0.82 x -3.8 (r(2)=0.80) at the calf level. CONCLUSION: TcpO2 measurement on the calf or buttock during exercise, is a reproducible measurement in patients with vascular claudication, specifically when corrected for exercise-induced systemic pO2 changes trough Delta-from-rest of oxygen pressure calculation.

[Long-term evolution of a thoraco-abdominal cryopreserved arterial allograft]. / Evolution à long terme d'une allogreffe artérielle cryoconservée en position thoraco-abdominale.

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.

[Secreting paraganglioma of the organ of Zuckerkandl. A case report]. / Paragangliome sécrétant de l'organe de Zuckerkandl. A propos d'un cas.

We report a case of a secreting retroperitoneal paraganglioma which developed on the organ of Zuckerkandl. Paraganglioma is a rare tumor of the paraganglioma system arising from undifferentiated cells of the neural crest. The originality of our observation comes from the secreting character of the tumor and the malignity proved by the local spreading to the wall of the inferior vena cava and the metastasis. The probable existence of a double primary localisation is also exceptional.

Spectral and profile analysis of Doppler recording following below-knee arterial distal bypasses.

BACKGROUND: Arterial below knee distal bypasses are associated with a high risk of thrombosis as compared to proximal bypasses. We assumed that before the bypass occludes, in the early postsurgical period, measurable velocity changes, and/or the presence of high intensity transient signals (HITS) would occur. SETTINGS: institutional reference center, hospitalized patients. SUBJECTS: satisfactory Doppler recording was obtained in 51 among 61 consecutive patients (32 males, 19 females, height: 165+/-7 cm, weight: 68+/-12 kg) suffering lower extremity arterial disease, that underwent saphenous (n=33), prosthetic (n=4) or sequential (n=14) below knee bypasses. We performed a spectral and profile analysis of a single postsurgical 2 hour Doppler recording at the ankle level and analyzed Doppler derived indices and clinical risk factors in the evaluation of the risk of bypass occlusion within 7 days following surgery. RESULTS: Primary patency at day 7 was observed in 41 of the 51 operated patients. The presence of HITS was found in approximately 30% of the patients and provided no information on the risk of thrombosis. No clinical variable was significantly associated with an increased risk of thrombosis. Whatever the duration of recording, the presence of a diastolic forward flow and wide systolic velocity changes were poor indicators of bypass thrombosis risk. On 512 beat recordings, a mean systolic velocity below 1630 Hz and a standard deviation of the resistance index >0.095 were associated with a 6.74 [1.6-28.4] (p<0.01) and 14.5 [3.6-58.9] (p<0.001) times increases in the risk of bypass occlusion respectively, compared with subjects that do not fulfill each criteria. CONCLUSIONS: Periods of transient asymptomatic no-flow-reflow events may be observed before the bypass irreversibly occludes. Prolonged Doppler recording should be preferred to short term analyses, to allow for the detection of these transient events and may provide potential indices for future research.