Coronary revascularization options evolve

The number of options that are in use or development for coronary revascularization or other treatment for ischemic heart disease is extraordinary. Given the mortality associated with coronary artery disease, it is unsurprising that it has been the focus of so much development.

Below are the options that have evolved for treatment of ischemic heart disease, inclusive of surgical, interventional, and other medical approaches.

Coronary Revascularization and Other
Ischemic Heart Treatment Options

Source: MedMarket Diligence, LLC

See also “Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022”, report #C500. Order online.

Peripheral Stenting Worldwide: Arterial, Venous, BMS, DES, AAA, TAA

First introduced about two decades ago as a bailout technique for suboptimal or failed iliac angioplasty, peripheral vascular stenting gradually emerged as a valuable and versatile tool for a variety of primary and adjuvant applications outside the domain of coronary and cerebral vasculature.  Today, peripheral vascular stenting techniques are commonly employed in the management of the most prevalent occlusive circulatory disorders and other pathologies affecting the abdominal and thoracic aortic tree and lower extremity arterial bed. Stents are also increasingly used in the management of the debilitating conditions like venous outflow obstruction associated with deep venous thrombosis and chronic venous insufficiency.

Notwithstanding a relative maturity of the core technology platforms and somewhat problematic opportunities for conversion to value-adding peripheral drug-eluting systems, peripheral vascular stenting appears to have a significant room for qualitative and quantitative growth both in established and emerging peripheral indications.

A panoply of stenting systems are available for the management of occlusive disorders and other pathologies affecting peripheral arterial and venous vasculature. Systems include lower extremity bare metal and drug-eluting stents for treatment of symptomatic PAD and critical limb ischemia resulting from iliac, femoropopliteal and infrapopliteal occlusive disease; stent-grafting devices used in endovascular repair of abdominal and thoracic aortic aneurysms; as well as a subset of indication-specific and multipurpose peripheral stents used in recanalization of iliofemoral and iliocaval occlusions resulting in CVI.

In 2015, these peripheral stenting systems were employed in approximately 1.565 million revascularization procedures worldwide, of which the lower extremity arterial stenting accounted for almost 1.252 million interventions (or 80.9%), followed by AAA and TAA endovascular repairs with 162.4 thousand interventions (or 10.5%) and peripheral venous stenting used in an estimated 132.6 thousand patients (or 8.6% of the total).

The U.S. clinical practices performed almost 528 thousand covered peripheral arterial and venous procedures (or 34.1% of the worldwide total), followed by the largest Western European states with over 511 thousand interventions (or 33.1%), major Asian-Pacific states with close to 377 thousand interventions (or 24.4%), and the rest-of-the-world with about 131 thousand peripheral stent-based interventions (or 8.4%).

Below is illustrated the global market for peripheral stenting by region in 2016 and by segment from 2014 to 2020.

Source: MedMarket Diligence, LLC; Report #V201. Available online.

 

Source: MedMarket Diligence, LLC; Report #V201. Available online.

Technologies at Medtech Startups, December 2016

Below is a list of technologies under development at startups identified thus far in December 2016 and included in the Medtech Startups Database:

  • Nanoparticle-based imaging for the treatment of epilepsy.
  • Implantable device for continuous relief of congestive heart failure.
  • Nanofiber technology for soft tissue repair.
  • Technology to facilitate intubation.
  • Medical device to manage skin complications suffered by ileostomy patients.
  • An implant for arthritis sufferers that mimics the natural motions of the joint.
  • Embolic protection device used during TAVR procedures.
  • Glucose monitor for diabetes using low-power RF/Microwave detection in fingertips.
  • Novel disinfection and sterilization solutions.
  • Drug delivery.
  • Dental and orthopedic applications of nanomaterials.
  • Catheter and guidewire technologies.

For a comprehensive list of the technologies at medtech startups identified by month, see link.

Cardiovascular Surgical and Interventional Procedures Worldwide, 2015-2022

In 2016, the cumulative worldwide volume of the the following CVD procedures is projected to approach 15.05 million surgical and transcatheter interventions:

  • roughly 4.73 million coronary revascularization procedures via CABG and PCI (or about 31.4% of the total),
  • close to 4 million percutaneous and surgical peripheral artery revascularization procedures (or 26.5% of the total);
  • about 2.12 million cardiac rhythm management procedures via implantable pulse generator placement and arrhythmia ablation (or 14.1% of the total);
  • over 1.65 million CVI, DVT, and PE targeting venous interventions (representing 11.0% of the total);
  • more than 992 thousand surgical and transcatheter heart defect repairs and valvular interventions (or 6.6% of the total);
  • close to 931 thousand acute stroke prophylaxis and treatment procedures (contributing 6.2% of the total);
  • over 374 thousand abdominal and thoracic aortic aneurysm endovascular and surgical repairs (or 2.5% of the total); and
  • almost 254 thousand placements of temporary and permanent mechanical cardiac support devices in bridge to recovery, bridge to transplant, and destination therapy indications (accounting for about 1.7% of total procedure volume).

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CABG: Coronary artery bypass graft; PCI: Percutaneous coronary intervention; AAA: Abdominal aortic aneurysm; TAA: Thoracic abdominal aneurysm; CVI: Chronic venous insufficiency; DVT: Deep vein thrombosis; PE: Pulmonary embolectomy.

Source: MedMarket Diligence, LLC; Report #C500, “Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022.” (To request report excerpts, click here.)

The Evolution of Coronary Revascularization Markets

Coronary artery bypass grafting (CABG) is the most common type of cardiovascular surgical intervention, which “bypasses” acute or chronic coronary artery obstructions via a newly created vascular conduit and thus reinstate normal or sufficient blood flow to the ischemic but still viable areas of the myocardium.

The majority of CABG surgeries (up to 75%) are still performed on the fully arrested heart which is accessed via a foot-long incision over the sternum and completely separated patient’s rib cage. Following a full sternotomy, the CABG patient is typically placed on extracorporeal cardiopulmonary bypass (CPB) with a heart-lung machine, which allows the surgeon to operate on a still and bloodless field. Simultaneously, the patient’s greater saphenous vein or internal mammary artery, or both are harvested (mobilized) for use as a bypass conduit in the ongoing procedure. Depending on the location, character and number of the coronary artery occlusions, the surgery might involve between one and seven coronary bypasses.

Once the bypasses are completed, the heart is restarted and, if it functions normally, the patient is removed from the heart-lung machine and the chest is closed up, the sternum is stabilized with stainless steel wire, and the chest and leg wounds are closed with sutures or clips. Patient’s recovery from a routine uncomplicated CABG usually involves seven to ten days of hospital stay, including two to three days spent in the cardiac intensive care unit.

Less Invasive CABG

Over the past decade, several less-invasive versions of the CABG were developed with the view of reducing morbidity and potentially serious complications associated with extensive surgical trauma and the use of aortic clamping and CPB. The current arsenal of less-invasive coronary artery bypass techniques includes minimally-invasive direct CABG (MIDCAB), full-sternotomy “off-pump” CABG (OPCAB), port-access CABG (P-CAB) with peripheral cannulation and endoclamping of aorta, and endoscopic computer (robotics)-assisted CABG (C-CAB).

Designed to limit surgical trauma of conventional CABG, the MIDCAB procedure is best suited for patients with occluding lesions either in the left anterior descending (LAD) artery, or the right coronary artery (RCA). In contrast to conventional CABG, it is performed on a beating heart without the use of CPB. In MIDCAB surgery, access to targeted arteries is achieved through a limited left anterior thoracotomy in the case of occluded LAD, and right thoracotomy or limited lateral thoracotomy in cases involving diseased proximal RCA or circumflex artery. Because of the smaller surgical trauma and off-pump performance (without aorta clamping), the MIDCAB procedure typically results in fewer complications, lower morbidity and shorter hospital stays compared to conventional CABG. However, its utility is limited to a subset of patients with one or two coronary vascular targets, which constitute a small fraction (<3%) of the total caseloads referred for CABG.

The OPCAB procedure is performed on a beating heart after reduction of cardiac motion with a variety of pharmacological and mechanical devices. These include slowing the heart rate with ß-blockers and calcium channel blockers and the use of special mechanical devices intended to stabilize the myocardium and mobilize target vessels. The use of various retraction techniques allows to gain access to vessels on the lateral and inferior surfaces of the heart. Because the OPCAB technique also involves surgical access via median sternotomy, its primary benefit is the avoidance of complications resulting from the use of cardiopulmonary bypass, not surgical trauma.

Over the past decade, the OPCAB surgery emerged as the most popular form of less-invasive coronary artery bypass procedures in the U.S, and Western Europe. By the beginning of this decade, an estimated 25% of all CABGs performed in these geographies were done without the use of CPB. However, in recent years, the relative usage of OPCAB techniques remained largely unchanged. In the view of many cardiac surgeons, the latter was predicated by the increasing morphological complexity of cases referred for CABG (rather than PCI) and generally superior immediate and longer-term bypass graft patency and patient outcomes obtainable with technically less-demanding on-pump CABG surgery.

In contrast to that, the relative usage of “neurological complications sparing” OPCAB techniques is significantly higher in major Asia-Pacific states reaching over 60% of all CABG procedures in China, India, and Japan.

The rarely used P-CAB procedure involves the use of cardiopulmonary bypass and cardioplegia of a globally arrested heart. Vascular access for CPB is achieved via the femoral artery and vein. Compared to the MIDCAB technique, the use of multiple ports allow access to different areas of the heart, thus facilitating more complete revascularization, and the motionless heart may allow a more accurate and reliable anastomosis. In distinction from conventional CABG, median sternotomy is avoided, which reduces trauma and complications. However, potential morbidity of the port-access operation includes multiple wounds at port sites, the limited thoracotomy, and the groin dissection for femoral-femoral bypass. The procedure is also technically difficult and time consuming and therefore has not achieved widespread popularity.

The Hybrid CABG-PCI procedure combines the use of surgical bypass (typically MIDCAB) and percutaneous coronary interventional techniques (angioplasty and stenting) for optimal management of multi-vessel coronary occlusions in high risk patients. The main rationale behind the utilization of hybrid procedure is to achieve maximally possible myocardial revascularization with minimally possible trauma and reduced probability of post-procedural complications. The most common variation of the hybrid revascularization involves MIDCAB-based radial anastomosis between the left anterior descending artery and left internal thoracic artery accompanied by the PTCA/stenting-based recanalization of less critical coronary artery occlusions.

CABG Utilization Trends and Procedure Volumes

Since the advent of coronary angioplasty in the late 1970s, the relative role and share of CABG procedures in myocardial revascularization have been steadily declining due to a continuing penetration of treated patient caseloads by a less invasive PTCA. This general trend was further expedited by the advent of coronary stents. At the very end of the past decade, the rate of transition towards percutaneous coronary interventions in myocardial revascularization started tapering off, primarily due to growing maturity of PTCA/stenting technology and nearly full coverage of patient caseloads with one- or uncomplicated two-vessel disease amendable through angioplasty and stenting. At the same time, a growing popularity of the less-invasive CABG regimens resulted in some additional influx into CABG caseloads from a no-option patient cohort. A less-invasive surgical coronary bypass also emerged as a preferred treatment option for some gray-area patients that were previously referred for sub-optimal PTCA and stenting to avoid potential complications of conventional CABG.

In 2006 – for the first time in about two decades – the U.S. and European volumes of CABG procedures experienced a visible increase, which was repeated in 2007 and reproduced on a smaller and diminishing scale in the following two years.

The cited unexpected reversal of a long established downward procedural trend reflected an acute (and, probably, somewhat overblown) end-users’ concern about long-term safety (AMI-prone late thrombosis) of drug-eluting stents (DES), which prompted a steep decline in utilization of DES in 2006, 2007, followed by a smaller and tapering decreases in 2008 and 2009 with corresponding migration of advanced CHD patients referred for radical intervention to bare metal stenting and CABG surgery.

In 2010 – 2015 the volume of CABG surgeries remained relatively unchanged, notwithstanding a visible decline in percutaneous coronary interventions and overall myocardial revascularization procedures.

In the forthcoming years, the cumulative global volume of CABG procedures is unlikely to experience any significant changes, while their relative share in coronary revascularization can be expected to decline from about 15.4% in 2015 to roughly 12.3% by the end of the forecast period (2022). The cited assertion is based on the expectation of eventual stabilization and renewal of nominal growth in utilization of PCI in the U.S. and Europe coupled with continuation of robust expansion in the usage of percutaneous revascularization techniques in Asia-Pacific (especially India and China, where PCI volumes were growing by 20% and 10% annually over the past half decade, according to local healthcare authorities).

In 2016, the worldwide volume of CABG surgeries leveled at approximately 702.5 thousand procedures, of which roughly 35.2% involved the use of less-invasive OPCAB techniques. During the forecast period, the global number of CABG procedures is projected to experience a nominal 0.1% average annual increase to about 705.9 corresponding surgical interventions in the year 2022. Within the same time frame, the relative share of less-invasive bypass surgeries is expected to register modest gains expanding to approximately 36.7% of the total in 2022.

Coronary Revascularization Procedures, 2015-2022 
(Figures in thousands)

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CABG and Primary PCI in Coronary Revascularization to 2022.

In, “Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022”, Report #C500, we forecast cardiovascular procedure utilization, caseload, technology trends, and device market impacts, for the U.S., Western Europe, Asia/Pacific, and Rest of World.

Cerebral thrombectomy procedures worldwide

In 2014, approximately 33.7 thousand cerebral thrombectomy procedures were performed worldwide, of which United States and largest European states accounted for roughly 46% and 37%, largest Asian states contributed 10.4% and the rest of the world added remaining 6.5%.

The 2014 global cerebral thrombectomy system sales were estimated at approximately $166 million, of which the United States accounted for about $79.1 million (or ~47.7%), followed by the largest Western European states with $59.4 million (or 35.8%), major Asian states with $17 million (or 10.2%) and the rest-of-the-world with $10.5 million (or 6.3% of the total).

In the view of the industry insiders and practicing neurointerventional radiologists, relatively modest volume of life-saving cerebral thrombectomy procedures and corresponding product sales appear to reflect still insufficient body of favorable clinical data and inhibiting impact of the published dubious findings from the major IMS-III study.

The latter compared first-generation cerebral thrombectomy techniques with standard medical (and tPA) therapy and asserted that endovascular clot retrieval interventions did not result in visible improvement in patient outcomes. The cited conclusions clearly contradict results of numerous randomized trials with available second-generation cerebral revascularization systems, which appear to documented superiority of the latter system in management of acute ischemic stroke caseloads.

It is generally assumed that the situation with end-user adoption is likely to improve dramatically in two-three years from now, when results of the ongoing major U.S. and international trials with novel cerebral thrombectomy devices become available.

Based on these assumptions, the cumulative worldwide volume of cerebral thrombectomy procedures is projected to experience accelerated growth to the end of the forecast period resulting in 10.8% overall average annual expansion of corresponding interventions in the forthcoming five years to an estimated 56.2 thousand total procedures worldwide in 2019.

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From: “Emerging Global Market for Neurointerventional Technologies in Stroke, 2014-2019”, Report #C310.

The worldwide market for cerebral clot retrieval systems is forecast to grow at a slightly slower pace expanding on average 10.1% per annum to about $268.4 million in the year 2019. Price pressure will keep sales growth lower than procedure volume gains.

The largest absolute dollar gains can be expected in the U.S. market (which is projected to add $55.9 million in corresponding device revenues), followed by the West European marketplace (+ $30.6 million), major Asian state business (+ $11.2 million) and the rest-of-the-world (+ $4.7 million).

Cardiac Rhythm Disorders and Implantable, Device-based Treatments

Cardiac rhythm disorders, also called arrhythmias or dysrhythmias, encompass a variety of relatively common acute and chronic conditions characterized by recurrent distortions in the electrical and contractile activity of the heart, which may cause clinically significant and progressive hemodynamic deficits and cardiopulmonary impairment.

According to the available statistics from the American Heart Association (AHA) and Heart Rhythm Society, symptomatic cardiac arrhythmias effect over 10 million Americans and account for approximately 20% of all chronic conditions treated by cardiologists in the United States.

The rate and rhythm of the heart are determined by the intrinsic rhythmicity of special tissues and structures within the heart wall muscle generated by the heart’s natural electrophysiological mechanism. Normal cardiac rate and rhythm ensure continued uninterrupted blood flow an associated supply of oxygen and nutrients to the brain and other vital organs. Irregularities in the rate, rhythm, or origin of a stimulus leading to myocardial contraction can potentially interrupt normal blood circulation, causing inadequate function of important body systems, stroke or sudden cardiac arrest and death. Heart pacing disorders usually degenerate and worsen over time.

Although cardiac arrhythmias may be triggered by congenital heart defects, in which the electrical system of the heart does not develop properly, non-congenital heart disorders are believed to be the most common causes of chronic arrhythmias. The latter is particularly true for ischemic heart disease, which results in reduced blood flow and oxygen delivery to heart tissue, and heart tissue scarring typically caused by myocardial infarction. Other causes of arrhythmia include abnormal blood and tissue concentrations of certain minerals; abnormalities of the autonomic nervous system, which is involved in cardiovascular regulation; stress; and use of alcohol, caffeine, illicit drugs, and tobacco, as well as diet pills and some other medications.

Cardiac arrhythmias are generally categorized according to their impact on heart rates. Bradycardia is an abnormally slow resting heart rate, whereas tachycardia is an abnormally high resting heart rate. Bradycardias are most commonly associated with SA node disease and/or various forms of heart block.

Tachycardias are usually classified by their origination site and may be subdivided into two broad categories, specifically, supraventricular tachycardias (SVTs) and ventricular tachycardias (VTs).

Below are shown the projected implantable pump generator placements by region from 2015 to 2022. These include pacemaker placements, implantable cardioverter defibrillator placements, and cardiac resynchronization therapy placements.

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Source: MedMarket Diligence LLC (Report #C500).

Requirements for acceptance of new peripheral stents in clinical practice

Stents are implantable devices designed as endoluminal scaffolds to maintain patency following recanalization of occluded or structurally compromised vascular (and non-vascular) circulatory conduits that enable energy supply and metabolic exchange in various organs and tissues of the human body. Palliative stenting has been routinely used for decades in the management of acute and chronic obstructions of gastro-intestinal, pulmonary and urinary tracts secondary to benign or malignant neoplasms or other cite-specific or systemic pathologies. However, a real explosion in utilization of stents was triggered in the early 1990s by the advent of vascular stenting devices, which allowed radically improved clinical outcomes of balloon angioplasty and supported its emergence as the first choice treatment modality for occlusive peripheral and coronary artery disease (PAD and CAD). By the end of 2014, more than three quarters of patients with acute and chronic arterial occlusions warranting intervention were referred for angioplasty-based therapy, which entailed placement of stenting devices in over 80% of commonly performed peripheral revascularization procedures.

To be accepted in clinical practices, stenting implants should satisfy a number of general and application-specific requirements relating to device biocompatibility, functional performance, and end-user and patient friendliness which are summarized in the exhibit below. In very general terms, stenting device biocompatibility refers to minimization of hostile immune responses (and other local and systemic adverse reactions) that are inevitably triggered by a direct contact of any implantable medical device with living tissues and bodily fluids in situ. For understandable reasons, biocompatibility depends primarily on the implant surface material, including such characteristics as chemical inertness and stability, corrosion resistance, etc. The stenting device biocompatibility can also be effected somewhat by the duration of its presence in situ and specifics of the deployment site and occlusion causing pathology.

The stent’s functional performance (or ability to maintain adequate scaffolding support and lumen patency for a desired period of time) represents a complex function of the device design/architecture and the relative static and dynamic strength of its base material. The chosen stenting device’s architecture and structural material predetermine it radial strength, longitudinal flexibility, conformability and foreshortening, as well as relative lesion coverage, fatigue and kinking resistance, circulatory flow obstruction, etc.

Finally, the stent’s end-user and patient friendliness are predicated both by the design concept of the delivery system and stenting device and refers to procedural convenience, predictability, safety, morbidity, availability of bail-out options, etc. The commonly acknowledged stenting system characteristics relating to the end-user/patient friendliness include low profile, flexibility, traceability, high radiopacity, compatibility with established transcatheter tools and techniques, ease of use and short learning curve, simplicity of retrieval in case of procedural failure, possibility of emergent /elective conversion to surgery, etc.

Selected Biomedical, Clinical and Technical Requirements
for Stenting Implants

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Source: MedMarket Diligence, LLC; Report #V201.

Coronary and venous interventions show inevitable Asia/Pacific dominance

Coronary revascularization, whether by bypass graft or percutaneous coronary intervention, drives an enormous amount of medtech business. Angioplasty catheters, guidewires, and the plethora of devices in cardiothoracic surgery represent many millions in sales annually. Manufacturers pursuing growth in these areas will see big, but slowing growth rates in the U.S., while markets in Asia/Pacific reflect the growing demand for cardio technologies. Already, these markets are surpassing western markets:

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Source: Report #C500.

While coronary applications have a long history, venous interventions have less, and procedure data shows that patient populations have not been fully tapped in any geographic region. Already, Asia/Pacific markets would appear to be on course to eclipse western markets, but not until after 2022, and will eclipse Western Europe markets before challenging the U.S.

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Source: Report #C500.

Coronary and Peripheral Vascular Dominate Global Cardiovascular Procedure Volumes

In 2016, the cumulative worldwide volume of the cardiovascular device procedures is projected to approach 15.05 million surgical and transcatheter interventions. This will include:

  • roughly 4.73 million coronary revascularization procedures via CABG and PCI (or about 31.4% of the total),
  • close to 4 million percutaneous and surgical peripheral artery revascularization procedures (or 26.5% of the total);
  • about 2.12 million cardiac rhythm management procedures via implantable pulse generator placement and arrhythmia ablation (or 14.1% of the total);
  • over 1.65 million CVI, DVT, and PE targeting venous interventions (representing 11.0% of the total);
  • more than 992 thousand surgical and transcatheter heart defect repairs and valvular interventions (or 6.6% of the total);
  • close to 931 thousand acute stroke prophylaxis and treatment procedures (contributing 6.2% of the total);
  • over 374 thousand abdominal and thoracic aortic aneurysm endovascular and surgical repairs (or 2.5% of the total); and
  • almost 254 thousand placements of temporary and permanent mechanical cardiac support devices in bridge to recovery, bridge to transplant, and destination therapy indications (accounting for about 1.7% of total procedure volume).

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Source: Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022.