|Year : 2020 | Volume
| Issue : 1 | Page : 13-17
Game changers in vascular and endovascular surgery
Varinder S Bedi1, Nikhil Sharma2
1 Chairman, Institute of Vascular and Endovascular Sciences-IVES-Sir Ganga Ram Hospital, New Delhi, India
2 Clinical Assisstant, Institute of Vascular and Endovascular Sciences-IVES-Sir Ganga Ram Hospital, New Delhi, India
|Date of Submission||06-Mar-2020|
|Date of Acceptance||06-Mar-2020|
|Date of Web Publication||16-Mar-2020|
Varinder S Bedi
Chairman, Institute of Vascular and Endovascular Sciences-IVES-Sir Ganga Ram Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Bedi VS, Sharma N. Game changers in vascular and endovascular surgery. Indian J Vasc Endovasc Surg 2020;7:13-7
”The angiographic catheter can be more than a tool for passive means of diagnostic observation; used with imagination, it can become an important surgical instrument.”
These were the words of Dr. Charles Dotter, speaking at the Czechoslovak radiological congress in June 1963, just months after he accidently recanalized an occluded right iliac artery. This was soon followed by intentional endovascular recanalization of the SFA of an 82-year-old patient with gangrene of the foot. The procedure was successful, and the wound healed in a matter of months  – a feat that was not short of magic!! [Figure 1].
|Figure 1: Pre and 5 months postpicture of the first patient successfully treated by Dotter|
Click here to view
Vascular and endovascular surgery has come a long way from the pioneering work of Dotter and others. The field now abounds in the adoption of new innovations in diagnostic and therapeutic arenas with many new Ground-breaking developments seen in the past few years. As we turn a new page and enter a new decade, the following brief description summarizes the game changers that the field of vascular and endovascular surgery has witnessed in the recent past. The millennium has been a turning point in the history of endovascular interventions. The vascular surgeon who started off purely as “surgeons” acquired the full armamentarium of endovascular skills, which was aided by newer developments in the past two decades. I propose to discuss the innovations under the following three heads:
- Innovations in diagnostics
- Innovations in pharmacotherapeutics
- Innovations in endovascular technology.
| Innovations in Diagnostics|| |
- The use of duplex ultrasonography in the diagnosis and management of vascular disease has also seen wider application in the past decade. Expertise has led to interventions being done on the basis of duplex alone, making computed tomography angiogram (CTA) redundant, especially in cases where contrast nephrotoxicity is a concern. The use of duplex ultrasound in hybrid OR's across the country is now a given, especially when it is used extensively at all stages of intervention right from guided arterial/venous punctures to the diagnosis of intraprocedural events (e.g. flow-limiting dissections/residual stenosis). The use of contrast-enhanced ultrasound (CEUS) has also recently found the application in the detection of endoleak following endovascular aortic repair (EVAR), which further mitigates the harmful radiation exposure to the patient
- IVUS is playing an increasingly important role in complex endovascular procedures. As opposed to angiography, which provides a “luminogram,” IVUS provides unparalleled in vivo axial imagery. This is critical in cases of type B aortic dissection where the outcomes with thoracic EVAR are undoubtedly improved with the use of IVUS
- Apart from aortic dissections, IVUS is increasingly justifying its management of peripheral arterial disease (PAD). Despite providing an accurate roadmap of the vessel lumen, angiography provides very little information about the vessel wall or plaque characteristics per se. Furthermore, angiography provides only limited information on the interaction of endovascular devices with the arterial wall. Here is where IVUS provides crucial information that guides the operator toward the application of appropriate therapy, thus improving the patency of intervention and thereby its outcomes
- In the past decade, IVUS has also established itself in venous intervention. Its superiority over conventional digital subtraction multiplanar venography for iliac vein obstructive lesions has been well established by the results published from the recently concluded VIDIO trial 
- Modern Cath Labs have progressed significantly in the use of innovative technologies. The use of three-dimensional (3D) image fusion angiographic software (e.g. – EVAR Guidance, Siemens) has facilitated the total endovascular management of complex aortic aneurysms using Fenestration, Branch, Chimney EVAR alone thus obviating the necessity of surgical debranching along with the additional benefit of reduced contrast use and radiation exposure., Along with this, contemporary cath laboratories offer improved operator safety in terms of greatly reduced surgeon radiation exposure. Accurate road-mapping facilitates ease in lesion crossing with improved outcomes. Another addition is the application of 2D perfusion Scan/iFlow in the management of CLTI. This software for analyzing the foot perfusion is based on a calculation of the change in contrast density per pixel over time with the images obtained before and after the revascularization procedure. The pre- and Post-images are evaluated for contrast arrival time, time to peak, wash-in rate, and area under the curve (AUC). The increment in perfusion is then estimated quantitatively by the change in the AUC
- Another feather in the cap for modern cath laboratories is the DynaCT/ExperCT technology. This technique generates CT-like images from “on table rotational angiographic acquisition.” Among various other utilities, DynaCT has found special application during EVAR for abdominal aortic aneurysms. It has been shown to be a powerful tool for the detection of endoleaks and other complications immediately following the procedure. It is more sensitive than uniplanar angiography and can be performed before shifting the patient from the operating table enabling immediate corrective measures if required. Moreover, studies have shown that the results from Dyna CT were similar to the 30-day follow-up MDCT angiography, which could possibly make it no longer necessary 
- A vexing problem often faced by vascular interventionalists is contrast-induced nephropathy, especially when the vascular patients are known to harbor borderline CKD (chronic kidney disease). A Path-breaking development in the prevention of kidney injury has been developed with the introduction of carbon dioxide angiography. Earlier systems have now given way to automated carbon dioxide angiography injectors such as Angiodroid, which can control the exact volumes and pressures of gas being injected using microcontrollers. Numerous publications have now established carbon dioxide as safe and as equally efficacious as iodine-containing contrast media 
- CT angiography of the aorta/lower extremity arterial system became possible with the introduction of multidetector CTA. While initially limited to 1-min acquisitions and 2–3-mm-thick sections, modern 64/128-row CT scanners can achieve acquisitions in seconds with submillimeter section thickness, greatly enhancing resolution, thus identifying the lesions which could earlier have been missed. Postprocessing software has become equally important as acquisition technology. The analysis of the often calcified arterial lumen is best achieved with curved planar reformation (CPR), or multipath curved planar reformations (MPR) thus rendering the images which are comparable to conventional digital subtraction angiography (DSA). Very recently, dual-energy CT technology has become available, which employs two different X-ray energy levels (e.g. 140 kVp and 80 kVp) to capture the images which allow the successful differentiation of iodine from vascular calcium. Similar advancements have been seen in the field of magnetic resonance angiography (MRA) in the form of MR time-of-flight imaging and gadolinium-enhanced contrast MRA with the effect that CTA and MRA have virtually replaced conventional DSA which was earlier considered indispensable.
| Innovations in Pharmacotherapeutics|| |
Anticoagulation can be rightly described as the backbone of vascular surgery even after a more than a century marking the discovery of heparin by McLean in 1916. The Path-breaking development of novel oral anticoagulants or direct oral anticoagulants (DOACs) has been a game changer in the field of vascular surgery in the past decade. The DOACs have been rigorously tested and have been approved for venous as well as arterial indications. Randomized controlled trials such as the RECOVER, EINSTEIN, AMPLIFY, and Hokusai-VTE have established Non-inferiority of these agents in the management of acute VTE as compared to traditional drugs (LMWH/Vitamin K antagonists) thus enabling totally oral and thus outpatient therapy for selected VTE patients simultaneously making monitoring less cumbersome as regular PT/INR monitoring is no longer necessary.
These agents have also found a place in the management of patients affected by PAD, the COMPASS trial has established that low-dose rivaroxaban combined with aspirin (100 mg) significantly reduced the incidence of major adverse cardiovascular and events in patients with atherosclerosis including peripheral arterial disease.
Thrombolytic agents have also started to become more widely utilized as essential pharmacological agents in the vascular surgeons' armamentarium. Newer thrombolytics such as alteplase and tenecteplase have found widespread use in thrombolysis in cases of acute DVT, PE, acute limb ischemia, and dialysis access/graft thrombosis. Newer thrombolytic devices such as AngioJet incorporate these agents in “Power-Pulse Mode” which enables additive pharmacologic and rheolytic thrombolysis to expedite thrombus removal, especially in cases where time is of the essence.
| Innovations in Endovascular Technology|| |
- Although the results from currently underway BASIL and BEST-CLI trials are yet to be published, recent data have confirmed that for CLTI, an endovascular- first approach is at least noninferior to bypass surgery even in longer lesions. However, the major drawback of current techniques is the potential for a suboptimal outcome due to vessel recoil as a result of extensive calcification. In this direction, the introduction of intravascular lithotripsy/lithoplasty (IVL) has been an important recent addendum. The device generates the pulsatile mechanical energy which disrupts calcium within the lesion and allows subsequent dilation of the lesion. Clinical efficacy and safety of this technique have already been demonstrated in the results from the DISRUPT PAD trial. The use of this technique adds to the ever-expanding collection of advanced hardware, including atherectomy and Re-entry devices, cutting and scoring balloons, cryoplasty, and drug-coated balloons/stents, which are tools in the endovascular surgeons repertoire in their fight against amputation. Although many would argue that the trials listed below are not admissible as Class I evidence, the list reiterates the fact that endovascular technology is here to stay and will surely evolve over time [Table 1]
- A recent introduction in the management of CLTI is the use of vasculomimetic stents and their impact on the spectrum of endovascular revascularization strategies. These stents such as the Supera (Abbott Inc.) are constructed by lacing together nitinol wires in an interwoven design which confers them superior resistance to external torsion forces, thereby enabling the deployment in hitherto “unstentable” anatomic locations (popliteal and common femoral arteries). These stents have already shown superior patency and freedom from target lesion revascularization as shown by the results from the SUPERB trial  and have already found a place on the shelves in Cath laboratories across the country
- Another new development in stent design has found the application in endovascular recanalization of occluded iliac venous segment. A total of seven dedicated venous stents have obtained CE mark approval and are being widely applied in the treatment of iliac venous pathology. Nitinol construction and high flexibility due to the presence of open-cell design are the features specific to these endoprosthesis which have shown promise as evident by the published results – a primary venous stent patency of 88% at 1 year has been achieved using the VENOVO stent as per interim data from the VERNACULAR study (Dake, M-Unpublished data-CIRSE-2019)
- The management of acute proximal DVT has witnessed a paradigm shift in the past decade. The introduction of pharmacomechanical catheter-directed thrombolysis (PCDT) using specialized devices (Angiojet, Indigo etc.) has led to expedited thrombus removal leading to the earlier restoration of vein patency, thus leading to veritable reduction in the incidence of postthrombotic syndrome (PTS) in accordance with the “Open-Vein Hypothesis.” Although the index publication from the ATTRACT trial was discouraging in terms of reduction in PTS, subsequent publications, including subgroup analysis, have demonstrated PTS reduction in iliofemoral DVT cohort, including most recent evidence (JVS-Venous, Jan 2020) proclaiming improved quality of life when PCDT is applied to proximal DVT. A significant yet often underestimated utility of acute thrombus removal for acute DVT has been the unmasking of underlying venous obstructive lesions (nonthrombotic iliac vein Lesions e.g., May-Thurner Syndrome) which can be treated simultaneously/subsequently allowing the improved longevity of interventions
- The treatment of varicose veins has also seen long strides since the original eponymous procedure described by Trendelenburg. High ligation and stripping have long been supplanted by endovenous methods such as RFA/EVLT. One drawback of these methods involved the use of heat-induced vein ablation, which led to post-procedure pain and made tumescent infusion mandatory as a heat sink. The introduction of Non-thermal and Non-tumescent methods of ablation which include Venaseal and Clarivein have made tumescent infusion unnecessary consequently enabling the ablations to be done under local anesthesia as truly office-based procedures. These methods have been wholeheartedly embraced by the Indian interventionalists as evident by 25 centers currently offering Venaseal after its nationwide launch in May 2019 (Medtronic Inc., Personal Communication)
- Complex aortic aneurysms have long been the Achilles's heel for the EVAR procedure. Specific problems such as short neck/tortuous anatomy and branch vessel involvement have led to solutions in terms of newer branched/fenestrated/surgeon modified endografts being deployed in increasingly greater numbers. The use of vascular closure devices for “pre” closure has now allowed percutaneous EVAR, i.e., PEVAR, a reality now being practiced at multiple centers across the country
- The field of carotid interventions has also seen some key advances. The CREST investigators initially reported equivalence in the outcomes of protected carotid stenting as compared to endarterectomy. A subsequent publication followed the two treatment arms out to 10 years and reported no significant difference with respect to the risk of periprocedural stroke, myocardial infarction, or death, thus providing evidence for noninferiority of protected CAS as compared to CEA. Another advancement in reducing periprocedural stroke during CAS was seen after the introduction of the TCAR (transcarotid) system. With this system, investigators have reported perioperative (30 days) stroke rates as low as 2.7%
- Central venous lesions arising in hemodialysis-dependent patients have always been refractory to treatment with better nephrology care and dialysis regimens, many of these patients are surviving long enough to experience central venous stenoses/occclusions and reocclusions which warrant intervention. Flexible nitinol stents/covered stents, drug eluting, and cutting balloons along with IVUS guidance have made endovascular interventions fruitful with longer patency of intervention. In patients with exhausted veins, the HeRO graft has been recently introduced which pairs an arterial inflow PTFE graft to a venous outflow catheter through a connector – an innovation deviced to bypass occluded central veins.
| What the Future Holds|| |
It is well-known that peripheral vascular interventions carry a higher risk of radiation exposure as compared to percutaneous coronary intervention. It is, therefore, logical that if a robotic system is developed for the performance of operator less interventions – vascular surgeons will be greatly benefitted by this. In this regard, the Magellan Robotic System received FDA clearance in 2012 for vascular interventions. This has now been succeeded by the CorPath robotic system, which was tested in the RAPID I and II trials, the results of which have shown promise in terms of feasibility and safety of these robotic devices.
Fiber Optic RealShape is a ground-breaking technology platform which enables real-time 3D visualization of the full shape of endovascular devices inside the body without the need for fluoroscopy.
This technology consists of equipment that sends the pulses of light through optical fibers that are integrated into intrabody devices. By sending laser into this fiber and then analyzing how it is reflected back, one can reconstruct and visualize the full shape of the devices in real time.
Percutaneous endovascular deep-vein arterialization has also seen a renaissance in its indication for “No option CLI” decades after it's very indigenous introduction by Prof Veera Reddy.
Percutaneous AVF for the dialysis has also become a reality with innovative systems such as the Ellipsys device.
Endovenous deep-vein value reconstruction is also on the horizon with intervene system coming up with a novel IVUS-guided BlueLeaf ® device which “recreates” damaged vein valves using a total endovascular approach.
Considering all the game changers in this millennium and looking at the crystal ball, it appears that endovascular Interventions are poised to take a gigantic leap with lesser traumatic and more predictable outcomes for patients thus leading to decreased mortality and morbidity due to vascular diseases.
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