The anterior saphenous vein. Part 2. Anatomic considerations in normal and refluxing patients. Endorsed by the American Vein and Lymphatic Society, the American Venous Forum, and the International Union of Phlebology.

BACKGROUND: The term Anterior Accessory of the Great Saphenous Vein suggests this is a branch tributary vein despite this vessel's anatomic features of a truncal vein. A multisocietal group suggested to designate this the anterior saphenous vein (ASV). This study was aimed to evaluate its ultrasound anatomy in normal and varicose limbs. METHODS: The clinical anatomy of the ASV was evaluated by narrative review of the literature. Additionally, the course of the ASV was evaluated in 62 limbs with no evidence of venous disease and 62 limbs with varicosities. RESULTS: The ASV length, patterns of origin and termination are reported in both normal and patients with varicose veins. Discussion of the patterns is supported by the narrative review of the literature. CONCLUSIONS: The ASV must be considered a truncal vein and its treatment modalities should be the same that for the great and small saphenous veins rather than a tributary vein.

Small saphenous vein aneurysm diagnosis and treatment.

Venous aneurysms are rare, particularly those arising from the superficial venous system. Current limited evidence suggests that congenital weakness of the vein wall, degenerative changes, trauma and inflammation are among potential causes. Surgical management has been the mainstay treatment modality of venous aneurysms. Surgical approaches and techniques should be tailored on a case-by-case basis, taking into consideration aneurysm location, size, shape and presence of complications (ie, rupture or thrombosis). In this report, we present a male patient in his late thirties who presented with right leg swelling and achiness 2 years following right lower extremity blunt trauma and was found to have a 3 cm small saphenous vein aneurysm extending to the saphenopopliteal junction. The patient was successfully treated with excision of the aneurysm via a posterior approach. This case report adds to the current literature and may help to define future treatment recommendations.

Unusual approach to popliteal vein bypass graft stenosis following failed angioplasty in popliteal entrapment syndrome.

Popliteal artery entrapment syndrome (PAES) is where the popliteal artery is compressed-typically by the medial head of the gastrocnemius muscle. PAES is typically treated surgically with popliteal artery release with or without bypass. Graft stenosis is a recognised complication of vein grafts. These are normally treated endovascularly. Endarterectomy of venous graft stenosis may be a useful tool in selected cases, where an endovascular approach was unsuccessful. Long-term follow-up of graft stenosis endarterectomy will allow us to determine effectiveness of this method of treatment where other options have failed.

Venous compression syndromes in females: A descriptive review.

Venous compression syndromes have been described, yet the role of sex is poorly understood. Although iliac vein compression has been discussed more often with the advent of newer technologies, research has fallen short on defining epidemiology, best practices for evaluation and treatment, and differences in responses to treatment between men and females. The authors report on iliac vein compression, nonthrombotic renal vein compression, and other venous compression syndromes in females. Literature searches of PubMed were performed using the following keywords: females/females and May Thurner, venous stenting, venous outcomes, deep venous disease, deep venous compression, venous stenting, renal vein compression, renal vein surgery/stent, popliteal vein entrapment, venous thoracic vein entrapment, and popliteal vein entrapment. The articles prompted the authors to research further as the referenced articles were reviewed. Sex representation has not been addressed adequately in the research of venous compression syndromes, making the discussion of best treatment options and long-term outcomes difficult. More specific understanding of epidemiology and response to interventions will only come from research that addresses these issues directly, understanding that some of these syndromes occur rarely.

[An overview of treatment options for a rare disease, aneurysm of the popliteal vein, in connection with a case]. / Egy ritka kórkép, a vena poplitea aneurysma kezelési lehetoségeinek áttekintése egy eset kapcsán.

INTRODUCTION: Popliteal vein aneurysm is a rare, but potentially life-threatening condition that can lead to deep vein thrombosis and/or pulmonary embolism. It is often asymptomatic, but symptoms may include pain, post-thrombotic syndrome or chronic venous insufficiency. An experienced physician may be able to detect a palpable mass in the popliteal fossa. Duplex ultrasound is the first line of diagnosis. CT or MR venography play a role in the diagnosis. OBJECTIVE: To review the international literature, explain the possible treatment options, and present our case. CASE REPORT: A 62-year-old female patient had a recurrent pulmonary embolism while on direct-acting oral anticoagulant therapy. Duplex ultrasound and MR angiography were performed and confirmed a partially thrombosed aneurysm of the right popliteal vein. Aneurysm resection and venorrhaphy were performed as treatment. At follow-up, ultrasound showed adequate flow in the deep venous system. 6 months later, the control MR angiography showed good flow without stenosis. There were no postoperative complications. Discussion and literature review: The pathomechanism of the disease remains unclear. Treatment options are conservative therapy and/or surgical intervention, but there is no consensus regarding the therapy of symptomatic or asymptomatic cases. There is no clear statement regarding the method and duration of postoperative anticoagulant therapy. CONCLUSION: In the case of recurrent pulmonary embolism, the possibility of a popliteal vein aneurysm should be considered. Ultrasound is a non-invasive, widely available initial diagnostic tool. In addition to conservative treatment, the possibility of surgical intervention can be considered. The surgical procedure described in our case was successful. Orv Hetil. 2023; 164(39): 1544-1549.

Institutional Experience With Venous Aneurysms - Insights On The Natural History And Outcomes Of Surgical Treatment.

INTRODUCTION: Venous aneurysms are rare, so their natural history is not fully understood. Indications for treatment are often determined by the location and size of the aneurysm; however, considering the scarcity of data, there are no specific recommendations. Surgery is the mainstay for venous aneurysm treatment, but some authors reported successful endovascular treatment. We intend to describe our experience with this type of rare disorder. METHODS: A post hoc observational study of a prospectively maintained registry including consecutive patients admitted with the diagnosis of a venous aneurysm at different locations between January 2007 and September 2021. Demographic data, anatomic location, and medical history, including trauma or venous surgery, were analyzed. All vascular reconstructions and outcomes have been evaluated. RESULTS: We identified 30 venous aneurysms in 24 patients. Fifteen patients were male (63%). The most common anatomical location was the popliteal vein (n=19; 63%). Four patients had multiple venous aneurysms, and three patients had synchronous arterial aneurysms. Twelve (63%) of the popliteal vein aneurysms identified were surgically treated, most commonly by tangential aneurysmectomy and lateral venorrhaphy. The average diameter at the time of surgery was 22,8±3,6 mm. After discharge, all patients were anticoagulated for 6 to 12 months, in most cases with rivaroxaban. With a median follow-up time of 32 months (12 - 168 months), primary patency was 92%. Aneurysm recurrence was only observed in one case (1/12; 8%) with non-occlusive thrombosis of the aneurysm 14 years after surgery. One patient had a 21 mm gemelar vein aneurysm, having been proposed for surgery, with thrombosis before the intervention. Two patients had common femoral vein aneurysms treated with partial aneurysmectomy and lateral venorrhaphy without thromboembolic events during follow-up. Two patients presented with portal system aneurysms, one associated with portal hypertension. No treatment was performed, and an increase in aneurysm size was observed during follow-up. Another patient presented with acute deep vein thrombosis on chronically thrombosed bilateral iliac vein aneurysms. Three patients had aneurysms of the superficial venous system associated with previous trauma, which were treated with simple ligation and excision. CONCLUSION: Venous aneurysms are rare and most commonly located in the popliteal vein, which seems to be associated with chronic venous disease. Treating these aneurysms, even without symptoms, can be important to avoid thromboembolic complications. However, close long-term follow-up with duplex ultrasound should be considered to detect late recurrence. Aneurysms from other locations are even rarer, and treatment decisions should be individualized, weighing the risks and benefits of the intervention.

Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation.

PURPOSE: To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES). METHODS: Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0-10). Significance was set to p < 0.05. RESULTS: TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different. CONCLUSION: TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE. TRIAL REGISTRATION: Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered.

Factors Affecting Recanalization in Femoropopliteal Deep Vein Thrombosis.

Effects of warfarin and new-generation direct oral anticoagulants (DOACs) on thrombus resolution after the treatment of deep vein thrombosis (DVT) are still unknown. The study aimed to investigate the effects of warfarin and DOACs on thrombus resolution after DVT treatment. Methods: The study included 666 patients who were diagnosed with femoropopliteal DVT between January 2016 and January 2022 and had complete medical records without missing data. Patients with and without recanalization were added to groups 1 (n = 396) and 2 (n = 270), respectively. Ultrasonography/venous Doppler examinations of the patients during follow-up were performed by 3 radiologists. Recanalization was defined as the presence of complete flow in the femoral and popliteal veins and the absence of residual venous thrombus. Results: Among the included patients, recanalization was observed in 59.5% patients. The mean follow-up period was 23.6 ± 17.8 (range 1-72; median 17) months. There was no difference between the 2 groups in terms of the types of drugs used in the treatment (P = .208). Cox regression models were used to investigate the factors affecting recanalization. Analysis of the variables having significant differences between both groups revealed the low rate of recanalization in patients with coronary artery disease (odds ratio [OR], 2.3%; 95% confidence intervals [CI]: 1.6-3.4; P < .001) and diabetes mellitus (OR, 1.5; 95% CI: 1.1-1.9; P = .009). Conclusion: Thrombus resolution after femoropopliteal DVT is not affected by the drugs used in the treatment.

Renal replacement therapy via popliteal vein for exhausted vascular access in emergency: A case report.

A 59 year-old man was admitted as his left antecubital arterio-venous fistula was thrombosed, and hemodialysis could not be succeeded for the last two sessions. It was a brachio-basilic fistula without transposition, which also required thrombectomy 8 months ago, and had been created 18 months before. He had multiple catheter insertions during the period of 6 years. Following the failed catheter insertions from both jugular and femoral veins, an ultrasound-guided venography via the left popliteal vein demonstrated the intact left popliteal and femoral vein with well-developed collaterals at the level of occluded left iliac vein. A temporary hemodialysis catheter was placed through the popliteal vein with an antegrade manner under ultrasound guidance in prone position, which effectively worked during hemodialysis sessions afterwards. Transposition of basilic vein was performed. Following the wound recovery, arterialized basilic vein has started to be used effectively for hemodialysis, and the popliteal catheter was displaced.

Point-Of-Care Ultrasound Screening for Proximal Lower Extremity Deep Venous Thrombosis.

Acute lower extremity deep venous thrombosis (DVT) is a serious vascular disorder that requires accurate and early diagnosis to prevent life-threatening sequelae. While whole leg compression ultrasound with color and spectral Doppler is commonly performed in radiology and vascular labs, point-of-care ultrasound (POCUS) is becoming more common in the acute care setting. Providers appropriately trained in focused POCUS can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. This paper describes a simplified yet validated approach to POCUS by describing a three-zone protocol for lower extremity DVT POCUS image acquisition. The protocol explains the steps in obtaining vascular images at six compression points in the lower extremity. Beginning at the level of the proximal thigh and moving distally to the popliteal space, the protocol guides the user through each of the compression points in a stepwise manner: from the common femoral vein to the femoral and deep femoral vein bifurcation, and, finally, to the popliteal vein. Further, a visual aid is provided that may assist providers during real-time image acquisition. The goal in presenting this protocol is to help make proximal lower extremity DVT exams more accessible and efficient for POCUS users at the patient's bedside.

Pedal Musculovenous Pump Activation Effectively Counteracts Negative Impact of Knee Flexion on Human Popliteal Venous Flow.

Knee scooters are commonly used for mobility instead of other devices. However, passive popliteal venous flow impedance has been observed with knee scooter usage ostensibly as a result of deep knee flexion. This study aimed to characterize the magnitude of impact knee flexion has on popliteal venous flow in relation to the degree of knee flexion when walking boot immobilized. Furthermore, the countervailing effect of standardized pedal musculovenous pump (PMP) activation was observed. Popliteal venous diameter and flow metrics were assessed with venous ultrasonography in 24 healthy individuals. Straight leg, crutch, and knee scooter positioning while wearing a walking boot and non-weight-bearing were compared. Flow was assessed with muscles at rest and with PMP activation. Of 24 participants, 16 (67%) were female. Twelve limbs (50%) were right sided. The mean age was 21.9 (SD = 3.0) years, and the mean body mass index was 21.9 (SD 1.9) kg/m2. Observer consistencies were excellent (intraclass correlation range = 0.93 to 0.99). No significant differences in mean vessel diameter, time-averaged mean velocity, and total volume flow occurred (all P > .01). Corresponding knee flexion effect sizes were small (range = -0.04 to -0.26). A significant decrease (-24%) in active median time-averaged peak velocity occurred between upright and crutch positions (20.89 vs 15.92 cm/s; P < .001) with a medium effect size (-0.51). PMP activation increased all flow parameters (all P < .001), and effect sizes were comparatively larger (>0.6) across all knee flexion positions.Clinical Significance: Knee flexion has a small to medium impact on popliteal venous return in healthy patients. Active toe motion effectively counters the negative effects of gravity and knee flexion when the ankle is immobilized.Levels of Evidence: Therapeutic, Level IV.

Cystic Adventitial Disease of the Popliteal Vein: A Case Report.

Venous cystic adventitial disease (VCAD) is a rare vascular anomaly located in the common femoral vein in most cases. We describe the case of a 59-year-old female patient with right leg edema who was misdiagnosed with deep vein thrombosis of the lower extremity at another hospital. Magnetic resonance angiography revealed a round mass in the popliteal vein, with a narrow lumen. Considering the location of the lesion, absence of a history of deep venous thrombosis and trauma, and clinical manifestations, the diagnosis is likely a popliteal vein adventitial cyst. Segmental popliteal vein resection and reconstruction were performed using a cylindrical great saphenous vein graft. No joint connection was found during the operation, and the postoperative pathology confirmed VCAD.

Distribution of Lower Extremity Deep Vein Thrombosis and Implications for Limited Compression Ultrasound Examinations.

BACKGROUND: Limited compression bedside ultrasonography (LCUS) including two-point, three-point, and extended compression examinations have become increasingly popular among emergency physicians to assess for lower extremity deep venous thrombosis (DVT). OBJECTIVE: Our objective in this study was to determine the prevalence and distribution of lower extremity DVT in sites identified by complete duplex ultrasonography (CDUS) that may potentially be missed using limited compression ultrasonography techniques. METHODS: This was a retrospective, multicenter study conducted at 12 hospitals within the Northwell Health system over a span of 4 years. Study participants (emergency department patients) underwent CDUS to assess for possible DVT. Images were reviewed and interpreted by radiologists and vascular surgeons at each of the participating institutions. RESULTS: A total of 42,487 CDUS examinations were performed, of which 3383 were positive for DVT. DVTs were deemed to be acute in 2664 (79%) and chronic in the remaining 21% on the basis of comparison with previous studies and appearance of the vein. Of the acute DVTs, 136 (5.1%) were confined to the common femoral vein, 116 (4.4%) to the femoral vein, 8 (0.3%) to deep femoral vein, 213 (8.0%) to popliteal vein, and 934 (35.1) to calf veins alone. CONCLUSIONS: In our study, a significant number of DVTs were identified in sites that may have been potentially missed on LCUS examinations, thereby supporting the use of complete duplex ultrasonography when available.

Popliteal cysts are not a risk factor for lower extremity deep vein thrombosis.

BACKGROUND: Popliteal cysts (PC) result from distension of the gastrocnemio-semimembranosous bursa. Published reports indicate coincident PC and deep vein thrombosis (DVT). Whether the presence of PC increase the risk of deep vein thrombosis (DVT) remains unclear. METHODS: Lower extremity venous Duplex ultrasound (DUS) reports were evaluated across the Mayo Clinic Enterprise (Rochester, Minnesota, Jacksonville, Florida, Scottsdale, Arizona, and the Mayo Clinic Health System) in patients ≥ 18 years of age. Natural language processing (NLP) algorithms were created and validated to identify acute lower extremity DVT and PC from these reports. To determine whether there is a link between PC and lower extremity DVT, the frequency of PC among cases (ultrasounds with acute DVT) were compared to controls (ultrasounds without acute DVT). RESULTS: A total of 357,703 lower extremities venous DUS were performed in 237,052 patients (mean age 63.3 ± 16.6, 54.4% were female) between 1992 and 2021. Acute DVT was identified in 32,572 (9.1%) DUS, and PC in 32,448 (9.1%). PC were seen in a lower frequency (8.0%) of ultrasounds with acute DVT than those without (9.2%) acute DVT (OR: 0.85, 95% CI: 0.82 to 0.89, p < 0.001). In a multivariate logistic regression model after adjusting for age, sex, and race, PCs were not positively associated with acute DVT (adjusted OR: 0.84, 95% CI: 0.81 to 0.88). CONCLUSIONS: PC are an incidental finding or an alternative diagnosis on lower extremity venous DUS, a finding that increases significantly with age. PC were not a risk factor in the development of lower extremity DVT.

Popliteal vein reflux is associated with increased rates of thrombotic complications after small saphenous vein closure procedures.

BACKGROUND: Venous insufficiency in the small saphenous vein (SSV) is significantly less common than venous insufficiency in the great saphenous vein; the impact of popliteal vein reflux on SSV closure procedural outcomes has yet to be studied. METHODS: A retrospective analysis was performed on 150 SSV closure procedures from 2015 to 2019. Preoperative demographic analysis was performed, after which univariate analyses were performed for postoperative occlusion rates and combined rates of endothermal heat-induced thrombus (EHIT) and endovenous foam-induced thrombus (EFIT). RESULTS: The cohort had a mean age of 58 years, and 116 (77%) were female. Fifty-four patients had C2 disease, 76 had C3 disease, 15 had C4 disease, 1 had C5 disease, and 4 had C6 disease. Twenty-three patients (15.3%) were noted to have popliteal vein reflux on their initial venous insufficiency ultrasound study, compared with 127 (84.6%) who did not. Treatment modalities included 84 radiofrequency ablations (56.0%), 37 polidocanol endovenous microfoam (24.6%), and 29 laser ablations (19.3%). When comparing patients with popliteal vein reflux with those without, there was no significant difference in the occlusion rates at their immediate postoperative visit (99.2% vs 95.6%) or at their 6-month postoperative visit (92.1% vs 91.3%). EHIT/EFIT was noted in 4 of the 23 patients with popliteal vein reflux compared with 4 of the 127 patients without popliteal vein reflux (17.3% vs 3.1%; P = .01). All eight instances of EHIT/EFIT were classified as either arteriovenous fistula class I or II EHIT or EFIT, and all were successfully treated without progression to deep vein thrombosis. CONCLUSIONS: The presence of popliteal vein reflux has no impact on postoperative occlusion rates at 6 months; however, it is associated with a significantly increased rate in EHIT and EFIT. Patients should be counseled on this increased risk should they undergo SSV treatment with known popliteal vein reflux.

Contemporary management and outcomes of peripheral venous aneurysms: A multi-institutional study.

OBJECTIVE: Extremity venous aneurysms result in the risk of pulmonary embolism (PE) and chronic venous insufficiency. At present, owing to the rarity of these aneurysms, no consensus for their treatment has been established. The purpose of the present study was to review the presentation, natural history, and contemporary management of extremity venous aneurysms. METHODS: We performed a retrospective, multi-institutional review of all patients with extremity venous aneurysms treated from 2008 to 2018. A venous aneurysm was defined as saccular or fusiform with an aneurysm/vein ratio of >1.5. RESULTS: A total of 66 extremity aneurysms from 11 institutions were analyzed, 40 of which were in a popliteal location, 14 iliofemoral, and 12 in an upper extremity or a jugular location. The median follow-up was 27 months (range, 0-120 months). Of the 40 popliteal venous aneurysms, 8 (20%) had presented with deep vein thrombosis (DVT) or PE, 13 (33%) had presented with pain, and 19 had been discovered incidentally. The mean size of the popliteal venous aneurysms presenting with DVT or PE was larger than that of those presenting without thromboembolism (3.8 cm vs 2.5 cm; P = .003). Saccular aneurysm morphology in the lower extremity was associated with thromboembolism (30% vs 9%; P = .046) and fusiform aneurysm morphology with a thrombus burden >25% (45% vs 3%). Patients presenting with thromboembolism were more likely to have had a thrombus burden >25% in their lower extremity venous aneurysm compared with those who had presented without thromboembolism (70% vs 9%). Approximately half of all the patients underwent immediate intervention, and half were managed with observation or antithrombotic regimen. In the non-operative cohort, three patients subsequently developed a DVT. Eight patients in the medically managed cohort went on to require surgical intervention. Of the 12 upper extremity venous aneurysms, none had presented with DVT or PE, and only 2 (17%) had presented with pain. Of the 66 patients in the entire cohort, 41 underwent surgical intervention. The most common indication was the absolute aneurysm size. Nine patients had undergone surgery because of a DVT or PE, and 11 for pain or extremity swelling. The most common surgery was aneurysmorrhaphy in 21 patients (53%), followed by excision and ligation in 14 patients (35%). Five patients (12%) had undergone interposition bypass grafting. A postoperative hematoma requiring reintervention was the most common complication, occurring in three popliteal vein repairs and one iliofemoral vein repair. None of the patients, treated either surgically or medically, had reported post-thrombotic complications during the follow-up period. CONCLUSIONS: Large lower extremity venous aneurysms and saccular aneurysms with thrombus >25% of the lumen are more likely to present with thromboembolic complications. Surgical intervention for lower extremity venous aneurysms is indicated to reduce the risk of venous thromboembolism (VTE) and the need for continued anticoagulation. Popliteal aneurysms >2.5 cm and all iliofemoral aneurysms should be considered for repair. Upper extremity aneurysms do not have a significant risk of VTE and warrant treatment primarily for symptoms other than VTE.

Impact of concomitant popliteal vein thrombosis in patients with acute iliofemoral deep vein thrombosis treated with endovascular early thrombus removal.

Background: Catheter-based thrombus removal (CBTR) reduces the risk of moderate to severe post-thrombotic syndrome (PTS) in patients with acute iliofemoral deep vein thrombosis (IF-DVT). However, the impact of concomitant popliteal DVT on clinical and duplex sonographic outcomes is unknown. Patients and methods: In this post-hoc analysis including the entire cohort of the randomized controlled BERNUTIFUL trial (48 patients), we compared clinical (incidence/severity of PTS assessed by Villalta score and revised venous clinical severity scores, rVCSS), disease-specific quality-of-life (QOL, CIVIQ-20 survey) and duplex sonographic outcomes (patency, reflux, post-thrombotic lesions) at 12 months follow-up between patients with IF-DVT with and without concomitant popliteal DVT treated by CBTR. Results: Overall, 48 IF-DVT patients were included (48% men, median age of 50 years), of whom 17 (35%) presented with popliteal DVT. At baseline, patients with popliteal DVT were older, had a higher body mass index and more important leg swelling. At 12 months, freedom from PTS (93% vs 87%, P=0.17), median total Villalta score (1 vs 1.5; P=0.46), rVCSS (2 vs 1.5, P=0.5) and disease-specific QOL (24 points vs 24 points, P=0.72) were similar between patient with and without popliteal DVT, respectively. Duplex sonographic outcomes were similar, except for more frequent popliteal post-thrombotic lesions and reflux (P=0.02) in patients with popliteal DVT. Conclusions: Relevant clinical outcomes 1 year after successful CBTR were favorable, regardless of the presence or absence of concomitant popliteal DVT. However, post-thrombotic popliteal vein lesions and reflux are more frequent in IF-DVT patients with popliteal involvement. Their impact on long-term outcomes remains to be investigated.